Purine derivatives having hypocholesterolemic activity

ABSTRACT

PURINE DERIVATIIVES OF THE FORMULA:   1-(R5-CO-R4-),2-R3,4,5-(-C(-R1)=A-C(-R2)=N-)IMIDAZOLE   WHEREIN A IS N OR N$O, R1 IS HYDROGEN, HALOGEN, HYDORYXL, MERCAPTO, LOWER ALKOXY, AR(LOWER)ALKOXY, LOWER AKYTHIO, AMINO, LLLOWER ALKYLAMINO, DI(LOWER)ALKYLAMINO, AR(LOWER)ALKYLAMINO, ACYLAMINO, HYDROXYAMINO, LOWER AKOXYAMINO, AR(LOWER) ALKOXYAMINO OR ARYLOXYAMINO, R2 AND R3 ARE EACH HYDROGEN, HALOGEN, HYDOXYL, MERCAPTO, AMINO, LOWER ALKYL, ARYL, LOWER ALKOXY, AR(LOWER)ALKOXY OR LOWER ALKYLTHIO, R4 IS LOWER ALKYLENE SUBSTITUTED WITH ONE OR MORE HYDROXYIS (BUT NO HYDROXYL GROUP BEING PRESENT AT THE CARBON ATOM ADJACENT TO THE RING NITROGEN ATOM) WHICH MAY BE PROTECTED WITH ACYL, LOWER OR HIGHER ALKOXY, A AR(LOWER)AKYL OR, WHEN A PAIR OF HYDROXYLS EXIST ON THE ALKYLENE GROUP, WHICH LOWER ALKYLIDENE OR AR(LOWER)ALKYLIDENE AND R5 IS HYDROXYL, LOWER OR HIGHER ALKOXY, AMINO, LOWER ALKYLAMINO OR DI(LOWER)ALKYLAMINO, AND THEIR SALTS, WHICH EXIBIT MAKED HYPOCHOLESTEROLEMIC ACTIVITY WHICH EXTREMELY LOW TOXICITY.

Filed March 24. 1970 1974 AKIRA TENSH-O ETAL 3,813,394

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PURINE DERIVATIVES HAVING 'HYPOCHOLESTEROLEMIC ACTIVITY J Filed March'24. 1970 4 Sheets-Sheet 4 3 23 JC w o omw 09. com 00m 009 00:. ooficom. 003. com". 009 ootbowfi oomw ooom 00mm ooomoomm 000% United StatesPatent ABSTRACT OF THE DISCLOSURE Purine derivatives of the formula:

wherein A is N or N O, R is hydrogen, halogen, hydroxyl, mercapto, loweralkoxy, ar(lower)alkoxy, lower alkylthio, amino, lower alkylamino,di(lower) alkylamino, ar(lower)alkylamino, acylamino, hydroxyamino,lower alkoxyamino, ar(lower) alkoxyamino or aryloxyamino, R

.and R are each hydrogen, halogen, hydroxyl, mercapto,

amino, lower alkyl, aryl, lower alkoxy, ar(lower)alkoxy or loweralkylthio, R is lower alkylene substituted with one or more hydroxyls(but no hydroxyl group being present at the carbon atom adjacent to thering nitrogen atom) which may be protected with acyl, lower alkyl,ar(lower)alkyl or, when a pair of hydroxyls exist on the alkylene group,with lower alkylidene or ar(lower)alkylidene and R is hydroxyl, lower orhigher alkoxy, amino, lower alkylamino or di(lower)alkylamino, and theirsalts, which exhibit marked hypocholesterolemic acivity with extremelylow toxicity.

This application is a continuation-in-part of copending application Ser.No. 861,808, filed Sept. 29, 1969, now abandoned which is acontinuation-in-part of copending application Ser. No. 851,057, filedAug. 18, 1969 now abandoned.

The present invention relates to purine derivatives, and theirproduction and use.

In the specification, the term lower used in connection wtih themoieties derived from alkanes such as alkyl or alkylene is intended tomean the one having 1 to 8 carbon atoms unless otherwise indicated.

The purine derivatives of the present invention include thoserepresentable by the formula:

I'll

7 1 5 I2 J t it I I wherein Ais N or N O, R is hydrogen, halogen (e.g.chlorine, bromine, iodine, fluorine), hydroxyl, mercapto,

ar(lower)alk0xy such as phenyl(lower) alkoxy (e.g. benv' ce zyloxy,phenethyloxy), lower alkylthio (e.g. methylthio, ethylthio, propylthio),amino, lower alkylamino (e.g. methylamino, ethylamino, propylarnino),di(lower) alkylamino (e.g. dimethylamino, diethylamino,methylethylamino), ar(lower) alkylamino such as phenyl(lower)alkylamino(e.g. benzylamino, phenethylamino), acylamino such as loweralkanoylamino (e.g. acetylamino, propionylamino, octanoylamino) orbenzoylamino, hydroxyamino, lower alkoxyamino (e.g. methoxyamino,ethoxyamino, propoxyamino), ar(lower)alkoxyamino such as phenyl(lower)alkoxyamino (e.g. benzyloxyamino, phenethyloxyamino) oraryloxyamino such as phenoxyamino; R and R are each hydrogen, halogen(e.g. chlorine, bromine, iodine, fluorine), hydroxyl, mercap-to, amino,lower alkyl (e.g. methyl, ethyl, propyl, isopropyl), aryl such asphenyl, lower alkoxy (e.g. methoxy, ethoxy, propoxy, isopropoxy),ar(lower) alkoxy such as phenyl(lower) alkoxy (e.g. benzyloxy,phenethyloxy) or lower alkylthio (e.g. methylthio, ethylthio,propylthio); R is lower alkylene preferably having 2 to 6 carbon atoms(e.g. ethylene, trimethylene, propylene) substituted with one or morebydroxyls (but no hydroxyl group being present at the carbon atomadjacent to the ring nitrogen atom) which may be protected with acylsuch as lower alkanoyl (e.g. acetyl, propionyl) or benzoyl, lower alkyl(e.g. methyl, ethyl, propyl, isopropyl), ar(lower)alkyl such asphenyl(lower) alkyl (e.g. benzyl, phenethyl) or, when a pair ofhydroxyls exist on the alkylene group, with lower alkylidene (e.g.ethylidene, propylidene, isopropylidene) or ar(lower)alkylidene such asphenyl(lower)alkylidene (e.g. benzylidene); and R is hydroxyl, lower orhigher alkoxy (e.g. methoxy, ethoxy, propoxy, isopropoxy, octyloxy,decyloxy, heptadecyloxy), amino, lower alkylamino (e.g. methylamino,ethylamino, propylamino) or di(lower)alkylamino (e.g. dimethylamino,diethylamino, methylethylamino). There are also included their saltssuch as metal salts (e.g. sodium salt, potassium salt, calcium salt),ammonium salt, amine salts (e.g. dimethylamine salt, trimethylaminesalt) and acid-addition salts, i.e. organic and inorganic acidadditionsalts (e.g. hydrochloride, hydrobromide, sulfate, nitrate, phosphate,tartrate, citrate).

Specific examples of the purine compounds [I] are as follows:

4-(purin-9-y1)-4-deoxy-D-erythronic acid,

4-(2-aminopurin-9-yl)-4-deoxy-D-erythronic acid,

4-( 8-aminopurin-9-yl)-4-deoxy-D-erythronic acid,4-(6-aminopurin-9-yl)-4-deoxy-D-erythronic acid,

lower alkyl 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate (e.g. methyl4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate,

ethyl 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate,

propyl 4-(6-aminopurin-9-yl)-4-deoxyD-erythronate,

butyl 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate),

4- (6-aminopurin-9-yl) -4-deoxy-D-erythronamide,

N-lower alkyl 4 (6-aminopurin-9-yl)-4-deoxy-'D-erythronamide (e.g.N-ethyl-4-(6-aminopurin-9-yl)-4-deoxy- D-erythronamide) N,N-di(lower)alkyl-4- 6-aminopurin-9-yl -4-deoxy-D- erythronamide (e.g.N,N-diethyl-4-(6-aminopurin-9- yl)-4-D-erythronarnide),

4-(6-aminopurin-9-yl)-4-deoxy-2,3-0-lower alkylidene- D-erythronic acid(e.g. 4-(6-aminopurin-9-yD-4- deoxy-2,3-O-ethylidene-D-erythronic acid,

4- (6-aminopurin-9-yl -4-deoxy- 2, 3-0-isopropylidene-D erythronicacid), I

4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-ar(lower)alkylidene-D-erythronicacid (e.g. 4-(6-aminopurin-9-yD-4- deoxy-2,3-O-benzylidene-D-erythronicacid),

7 lower alkyl 4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-lower lower alkoxy(e.g. methoxy, ethoxy, propoxy, isopropoxy),

alkylidene-D-erythronate (e.g. methyl 4-(6-aminopurin-9-yl)-4-deoxy-2,3-0'-isopropylidene-D-erythronate,

ethyl 4-(6-aminopurin-9-yl)14-deoxy-2,3-0-isopropy1idene-D-erythronate)N-l'ovver alkyl -4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-

lower a1kylidene-D-erythronamide (e.g. Nethyl-4-(6-aminopurin-Q-yl)-4-deoxy-2,3-O-isopropyIidene-D- er'ythronamide) 4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-di(lower)- alkanoyl-D-erythronic acid(e.g. 4-(6-aminopurin-9- yl)-4-deoxy-2,3-O-diacetyl-D-erythronic acid,

4-( 6-aminopurin-9-yl)-4-deoxy-2,3-O-dipropionyl-D- erythronic acid),

lower alkyl 4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-di(lower)alkanoyl-D-erythronate (e.g. methyl 4-(6- aminopurin-9-yl-4-deoxy-2,3 -O'-diacetyl-D- erythronate) erythronic acid (e.g.4-(6-amino-8-methylpurin-9-yl)- 4-deoxy-Derythronic acid,

I 4-(G-amino-S-ethylpurin-Q-yl) -4-deoxy-D-erythronic acid)4-6-amino-8-lower alkylpurin-9-y1)-4-deoxy-2,3-O-lower4-(6-amino-8-hydroxypurin-9-yl)-4-deoxy-D-erythonic acid,

4- (Z-lower alkylthio-6-arninopurin-9-yl) -4-deoxy-D-erythronic acid(e.g. 4'(Z-metbylthio-6-aminopurin-9-yl)-4- deoXy-D-erythronic acid,

4- (2-ethylthio-6-aminopurin-Q-yl) -4-deoxy-D-erythronic acid),

4-(2-lower alkyl-6-aminopurin-9-yl)-4-deoXy-D-erythronic acid (e.g.4-(2-methyl-fi-aminopurin-Q-yl)-4-de0xy- D-erythronic acid),

4-(2,6-diaminopurin-9-yl)-4-deoxy-D-erythronic acid,

4- Z-hydroxy-6-aminopurin-9-yl) -4-deoxy-D-erythronic acid,

4-(6-1ower alkylaminopurin-9-yl)-4-deoxy-D-erythronic acid (e.g.4-methy1aminopurin-9-yl)-4-deoxy-D-erythronic acid,

4 ethylaminopurin-9-yl)-4-deoxy-D-erythronic acid,

4- (6-buty1aminopurin-9-yl -4-deoxy-D-erythronic acid) 4-(6-loweralkylaminopurin-9-yl)-4-deoxy-2,3-O-lower alkylidene-D-erythronic acid(e.g. 4-(ethy1aminopurin-9-yl)-4-deoxy-2,3-O-isopropylidene-D-erythronic acid),

4- 6 di- (lower) alkylaminopurin-Q -yl -4-deoxy-D-erythronic acid (e.g.4-(6-dimethylaminopuri11-9-yl)-4- deoxy-D-erythronic acid,

4-(6-diethylaminopurin-9-yl)-4-deoxy-D-erythronic acid), k

4-(6-hydroxyaminopurin-9fyl)-4-deoxy-D-erythronic acid,

4- [6-pheny1 (lower) alkyl aminopurin-9 -y1] -4-de oxy-D- erythronicacid (e.g. 4-(fivbenzylaminopurin-9-yl)-4- deoXy-D-erythronic acid,

4-('6-phenethylaminopurin-9-yl)-4deoxy-D-erythronic acid), 7 1

4-(6-benzoylarninopurin-9-yl)-4-deoxy-D-erythronic acid,4-(6-hydroxypurin-9-yl) 4-deoxy-D-erythronic acid, lower alkyl4-(6-hydroxypurin-9-yl)-4-dcoxy-D-erythro nate (e.g. methyl 4(6-hydroxypurin-9-yl)-4-deoxy-D- -lerythronate,

ethyl 4- (6-hydroxypurin-9-y1)-4deoxy-D-erythronate),

4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronamide,

lower alkyl 4-(6-hydroxypurin-9-yl)-4-deoxy-2,3-O-di(lower)alkanoyl-D-erythronate (e.g.methyl4-(6-hydroXypurin-9-yl)-4-deoXy-2,3-O-diacety1-D-erythronate,ethyl 4-(6-hydroxypurin-9-yl)-4-deoxy-2,S O-diacetyI-D erythronate)4-(6,8-dihydroxypurin-9-yl)-4-deoxy-D-erythronic acid,

4- (2,6-dihydroxypurin-9-yl -4-deoxy-D-erythronic acid,

4-(2-arnino-6-hydroxypurin-9-yl)-4-de0xy-D-erythronic acid,

4-(6-ha1opurin-9-yl)-4-deoxy-D-erythronic acid' (e.g. 4-

( 6-chloropurin-9-yl -4-deoxy-D-erythronic acid,

4-(6-bromopurin-9-yl)-4-deoxy-D-erythronic acid),

4-(6-halopurin-9-yl)-4deoXy-2,3 O-loWer alkylidene-D erythronic acid(e.g. 4-(6-chloropurin-9 y1)A-deoxy- 2,3O-isopropylidene-D-erythronicacid,

4-(6-bromopurin-9-yl)-4-deoxy-2,3-O-isopropylidenc-D- erythronic acid),

4-(6-mercaptopurin-9-yl)-4-deoxy-D-erythronic acid,

4- (-6-lower alkylthiopurin-9-yl)-4-deoxy-D-erythronic acid (e.g.4-(6-methy1thiopurin-9-yl)-4-deoxy-D-erythronic acid,

4-(6-ethylthiopurin-9-yl)-4-deoxy-D-erythronic acid),

4-(6-lower alkoxypurin-9-yl)-4-deoxy-Derythronic acid (eg.4-(6-methoxypurin-9-yl)-4-deoxy-D-erythronic acid),

4- (6-lower alkanoylaminopurin-Q-yl) -4-deoxy-D-erythronic acid (e.g.4-(6-acety1aminopurin-9-yl)4-deoxy- 'D-erythronic acid,

4-(fi-butylaminopurin-Q-yl) -4-deoxy D-erythronic acid),

3-(6-aminopurin-9-yl-2rhydroxy-3-hydroxymethylpropionic acid,

6-amino-9-(3-carboxy-2,3-dihydroxypropyl)-purin-loxide,

6-amino-9-(3-carboxy-2,3-isopropylideneoxypropyl)e r I purin-l-oxide, 0

4-(6-aminopurin-9-yl)-4-deoxy-L-threonic acid, etc.

N N\ by t if 4- (6-Aminopurin-9-yl -4-deony-D-erythronic acid Thecorrectness of the structure has been evidenced by identification of aspecimen of 4-(6-aminopurin-9-yly4- deoxy-D-erythronic acid, synthesizedartificially. Developing from this finding, there have been synthesizeda number of chemical compounds having the formula [I], and thepossession of marked hyprocholesterolemic activity by them has beenconfirmed. 1

Accordingly, a basic object of-"the present invention is to embody thehypochloesterolemic substance. Another object of this invention is toembody the artificial purine compounds [I] having hypocholesterolernicactivity. A further object of the invention is to embody a method forpreparing the hypochloesterolemic substance from Lentinus edodes.A'still furtherobject of the invention is to embody a method forsynthesis of-the novel purine compounds [I]. These and other objectswill be apparent to those conversant with the art to which the presentinvention pertains from the subsequent descriptions.

According to the present invention, the hypocholesterolemic substance isobtained by a method which comprises extracting Lentinus edodes withwater or aqueous alcohol, passing the extract through an acidic or abasic ion-exchange resin to adsorb the active component thereon, elutingthe ion-exchange resin with an acidic or a basic solution, passing theeluate through an adsorbent to adsorb the active substance thereon,eluting the adsorbent with a solvent, collecting the fractions showingan adsorption around 260 m in the ultraviolet absorption spectrum andremoving the solvent from the collected fractions.

Lentinus edodes is first extracted with water or aqueous alcohol. Thestarting plant may be fresh, dried or crumbled ones. The water to beused as the extraction solvent may be water itself or water acidifiedwith an acid or alkalified with an alkali. Examples of the acid aremineral acids (e.g. hydrochloric acid, sulfuric acid), perchloric acid,acetic acid, trichloroacetic acid, etc. Examples of the alkali areammonium hydroxide, sodium hydroxide, potassium hydroxide, etc. The acidor alkali may be also used in the form of a buffer solution. The alcoholto be employed as the extraction solvent may be, for instance, methanol,ethanol, isopropanol or the like. When Lentinus edodes is the fresh one,the use of absolute alcohol is substantially same as that of aqueousalcohol and fallen within the scope of the present invention.

The resulting extract is passed through an acidic or a basicion-exchange resin with or without previous concentration to adsorb theactive component thereon. Prior to the passing, the said extract may betreated with a suitable solvent such as ether to extract impurematerials. As the acidic or basic ion-exchange resin, there may beexemplified strongly acidic ones having sulfonic groups, weakly acidicones having carboxyl groups, strongly basic ones having quaternaryammonium groups or weakly basic ones having primary to tertiary aminogroups, among which the use of the strongly acidic or basic one ispreferred.

The acidic or basic ion-exchange resin is then eluted with an acidic ora basic solution. As the acidic or basic solution, there may be employedaqueous hydrochloric acid, aqueous ammonia, pyridine-acetic acid buffer,etc.

Then, the eluate is passed through an adsorbent with or withoutconcentrating and dissolving water previously to adsorb the activesubstance thereon. Examples of the adsorbent are ion-exchange resin,silica gel, alumina, diatomaceous earth, cellulose powder, magnesiumsilicate, calcium sulfate, Cephadex, active carbon, etc.

The adsorbent is then eluted with an organic or inorganic solvent.Examples of the solvent are aqueous ammonia, aqueous hydrochloric acid,acidic aqueous alcohol, pyridine-acetic acid bufier, etc. For elutingthe active substance effectively, there may be preferably adopted agradient elution procedure where the concentrations of the elutionsolvent are gradiently changed.

Among the thus obtained eluates, the fractions showing an absorptionaround 260 m in the ultraviolet absorption spectrum are collected andconcentrated, preferably under reduced pressure, to dryness.

The thus obtained crude product may be crystallized from water, ifnecessary, with previous repetition of the above adsorption and elutionoperations to give the pure active substance.

The crystalline active substance has the following physico-chemicalproperties:

(1) Elementary analysis (for crystals after drying at 80 to 90 C. for 2hours): C, 42.83%; H, 4.41%; N, 26.96%; 0, 25.32%.

(2) Molecular weight:

The methyl ester (M.P. 231 C. (decomp.)) obtained by methylating theactive substance: 276 (determined by mass spectrum).

The diacetate methyl ester (M.P. 225 C. (decomp.)) obtained byacetylating and methylating the active substance: 351 (determined bymass spectrum).

(3) Melting point: 279 C. (decomp.).

(4) Specific rotation: [a] +31 (c.=0.46, in dimethylsulfoxide).

(5) Ultraviolet absorption spectrum:

(6) Infrared absorption spectrum:

In a Nujol mull, the active substance affords a char acteristic band at1690 cm? (cf. FIG. 4 in the attached drawings).

(7) Solubility: insoluble in methanol and ethanol; sparingly soluble inwater but fairly soluble in acidic and basic water.

(8) Coloring reaction: negative in Molisch reaction, orcinol test andammonium molybdate test; positive in periodic acid-benzidine test.

In addition, the active substance aifords singlets at 8.01 p.p.m. (6)and 8.15 p.p.m. (a) and a wide singlet at 7.12 p.p.m. (6) for twohydrogen atoms which can be exchanged with heavy water in the nuclearmagnetic resonance. Further, it is methylated with diazomethane and alsois diacetylated with acetic anhydride and pyridine, from which thepresence of a carboxyl group and two hydroxyl groups may be presumed.

'On the basis of these and other physico-chemical properties, thechemical structure of the crystalline active substance has beendetermined as represented by the said formula [I], i.e. 4-(6-aminopurin9 yl) 4 deoXy-D- erythronic acid.

For synthesis of the purine compounds [I], there may be adopted variousmethods, most of which are fallen in the following classification:

(1) Construction of the fundamental structure (purine nucleus+9-sidechain) (1-1) Ring closure 1-1-1) From pyrimidine nucleus (1-1-2) Fromimidazole nucleus (l-2) N-Substitution (2) Conversion on the fundamentalstructure (2-1) Hydrolysis (2-2) Reduction (2-3) Amination (2-4)Esterification (2-5) Amidation (26 -Acylation (2-7) Acetalation (28)Other conversions Some typical procedures in each class will behereinafter illustrated in detail.

(11l) RING CLOSURE FROM PYRIMIDINE NUCLEUS One of the procedures fallenin this category is representable by the following formulae:

wherein R is hydrogen, halogen (e.g. chlorine, bromine, iodine,fluorine), hydroxyl, mercapto, lower alkoxy (e.g. methoxy, ethoxy,propoxy, isopropoXy), ar(lower)a1koxy such as phenylflower) alkoxy (e.g.benzyloxy, phenethyloxy), lower alkylthio (e.g. methylthio,'ethylthio,propylthio), amino, lower alkylamino (e.g. methylamino, ethylamiuo,propylamino), di(lower)alkylarnino (e.g. dimethylamino, diethylamino,methylethylamino), a.r(lower)alkylamino such as phenyl(lower)alkylamino(e.g. benzylamino, phenethylamino), hydroxyamino, lower alkoxyamino(e.g. methoxyamino, ethoxyamino, propoxyamino), ar(lower)alkoxyaminosuch as phenyl(lower)alkoxyamino (e.g. benzyloxyamino,phenethyloxyamino) or aryloxyamino such as phenoxyamino; R is hydrogen,halogen (e.g. chlorine, bromine, iodine, fluorine), hydroxyl, mercapto,amino, lower alkyl (e.g. methyl, ethyl, propyl, isopropyl), aryl such asphenyl, lower alkoxy (e.g. methoxy, ethoxy, propoxy, isopropoxy),ar(lower)alkoxy such as phenyl(lower)alkoxy (e.g. benzyloxy, phenethyloxy) or lower alkylthio (e.g. methylthio, ethylthio, propylthio); R ishydrogen, hydroxyl, mercapto, amino, lower alkyl (e.g. methyl, ethyl,propyl, isopropyl) or aryl such as phenyl; R is lower alkylenepreferably having 2 to 6 carbon atoms (e.g. ethylene, trimethylene,propylene) substituted with one or more hydroxyls (but no hydroxyl groupbeing present at the carbon atom adjacent to the ring nitrogen atom)which may be provided with acyl such as lower alkanoyl (e.g. acetyl,propionyl) or benzoyl, lower alkyl (e.g. methyl, ethyl, isopropyl),ar(lower)alkyl such as phenyl(lower)alkyl (e.g. benzyl, phenethyl) or,when a pair of hydroxyls exist on the alkylene group, with loweralkylidene (e.g. propylidene, isopropylidene) or ar(lower)alkylidenesuch as phenyl(lower)alkylidene (e.g. benzylidene); R is hydroxyl, loweror higher alkoxy (e.g. methoxy, ethoxy, propoxy, isopropoxy, octyloxy,decyloxy, heptadecyloxy), amino, lower alkylamino (e.g. methylamino;ethylamino, propylamino) or di(lower)al kylamino (e.g. dimethylamino,diethylamino, methylethylamino); X is amino, nitro, nitroso, aryldiazosuch as phenyldiazo or acylamino such as formylamino or loweralkanoylamino (e.g. acetylamino, propionylamino, butyrylamino) and R R Rand R are each as defined above.

The pyrimidine compound [II] is subjected to a chemical treatmentsuitably selected on the kind of the symbol X in the former to give thepurine compound [Ia].

For instance, the pyrimidine compound II: X=amino] is reacted withformic acid or its functional derivative such as formamide, lower alkylformate, N,N-di(lower)- alkylformamide, lower alkyl orthoformate, loweralkyl formimidate, sodium dithioformate or formamidine, if necessary,followed by heating or treatment with a base. The main reaction isusually carried out at a temperature from room temperature to theboiling temperature of the reaction medium, if necessary, in a solventsuch as water, methanol or ethanol. When desired, there may be used acondensing agent such as hydrochloric acid, acetic anhydride, sodiumalkoxide or phosphorus oxychloride depending on the kind of the reagent.The subsequent treatment with a base such as alkali metal hydroxide(e.g. sodium hydroxide, potassium hydroxide), alkaline earth metalhydroxide (e.g. calcium hydroxide, magnesium hydroxide), alkali metalalkoxide (e.g. sodium methoxide, potassium methoxide, sodium ethoxide)or tertiary amine (e.g. trimethylamine, triethylamine,N-methylpiperazine, pyridine) is ordinarily etfected in a solvent suchas water or aqueous alcohol.

Further, for instance, the pyrimidine compound [Hz X=amino] is reactedwith a thiocarbonic acid derivative such as thiophosgene, thiourea,sodium xanthogenate, potassium xanthogenate, carbon disulfide, dimethylthiocarbonate, diethyl thiocarbonate or l,1'-(thiocarbonic acid)diimidazole. The reaction is normally performed in a solvent such aswater, methanol, ethanol or propanol at a temperature from roomtemperature to the boiling temperature of the reaction medium, ifnecessary, in the presence of a condensing agent such as alkali metalalkoxide (e.g. sodium methoxide, sodium ethoxide, potassium ethoxide) ortertiary amine (e.g. triethylamine pyridine).

Further, for instance, the pyrimidine compound [11:

X=nitro, nitroso or aryldiazo] is reduced in the presence of formicacid, if necessary, followed by heating or treatment with a base. Forthe reduction, there may be adopted the combination of a metal (e.g.iron, tin, zinc) 'with an acid (e.g. hydrochloric acid, acetic acid),the combination of a metal (e.g. sodium, amalgamated sodium, amalgamatedaluminum, zinc, iron) with water or an alkanol (e.g. methanol, ethanol),a sulfide (e.g. ammonium sulfide, ammonium hydrosulfide, sodium sulfide,sodium polysulfide, sodium hydrosulfide, hydrogen sulfide), sodiumdithionite or sodium bisulfite, phenylhydrazine or hydrazine, thecombination of titanium trichloride with hydrochloric acid, thecombination of hydroiodic acid with hypophosphorous acid, electrolyticreduction or the like. Particularly preferred is catalytic reductionusing a cata lyst such as platinum, platinum oxide, palladium, palladiumoxide, palladium-carbon, palladium-barium sulfate, palladium-bariumcarbonate, palladium-silica gel, rhodium, iridium, ruthenium, nickeloxide, Raney nickel, Raney cobalt, reductive iron, Raney iron, reductivecopper, Raney copper, Ullmann copper or zinc. The reduction is usuallyeffected in a solvent suitably selected depending on the kinds of thereducing agent and the catalyst. As the base for the subsequenttreatment, there may be used alkali metal hydroxide (e.g. sodiumhydroxide, potassium hydroxide), alkaline earth metal hydroxide (e.g.calcium hydroxide, magnesium hydroxide), alkali metal alkoxide (e.g.sodium methoxide, sodium ethoxide, potassium ethoxide), tertiary amine(e.g. trimethylamino, triethylamine, N-methylpiperazine, pyridine) orthe like. In the case, the treatment is normally eifected in a solventsuch as Water or aqueous alcohol.

Furthermore, for instance, the pyrimidine compound [II: X=acylamino] isheated or treated with a base. The heating is usually carried out in asolvent (e.g. formamide, dimethylformamide, dimethylsulfoxide),preferably in the presence of a dehydrating agent (e.g. aceticanhydride). As the base, there may be exemplified alkali metal hydroxide(e.g. sodium hydroxide, potassium hydroxide), alkaline earth metalhydroxide (e.g. calcium hydroxide, magnesium hydroxide), alkali metalalkoxide (e.g. sodium methoxide, sodium ethoxide, potassium ethoxide),tertiary amine (e.g. trimethylamine, triethylamine, N-methylpiperazine),ammonia, etc. The treatment with the base is normally executed in asolvent such as water, alcohol or aqueous alcohol. 1

In the course of the said various processes, one or more of thesubstituents represented by the symbols R R R and R may be influenced.Some examples of such influence are as follows: conversion of thehalogen atom represented by R, or R into hydroxyl, lower alkoxy ormercapto, conversion of the acylated or etherified hydroxyl group in Rinto free hydroxyl, conversion of the lower alkoxy or amino grouprepresented by R into free hydroxyl, etc.

The starting pyrimidine compounds [II] can be produced by variousmethods, some of which are shown in the following scheme:

[1 Step). 1

wherein R R R R and X are each as defined above, R is acyl such asformyl or lower alkanoyl (e.g. acetyl, propionyl, butyryl) and X ishalogen (e.g. chlorine, bromine).

The reaction in the step 1 is carried out by treating the compound [11']with a reagent of the formula:

[11'] wherein R and R are each as defined above.

The reaction is applicable to any of the compounds [II] irrespective ofthe meaning of X.

Specific examples of the compound [II'] as the starting material are2,6-dihydro-4-chloro-S-nitropyrimidine,6-amino-5-nitro-4-chloropyrimidine,6-hydroxy-5-nitro-4-chloropyrimidine,2-amino-6-hydroxy-5-nitro-4-chloropyrimidine,6-mercapto-5-nitro-4-chloropyrimidine,2-butyl-4,6-dichloro-5-nitropyrimidine,2-butyl-4,6-dichloro-5nitropyrirnidine,6-hydroxyamino-5-nitro-4-chloropyrimidine,2-methyl-4,6-dichloro-S-nitropyrimidine, 2,4-dichloro-5-nitropyrimidine,2,4,6-trichloro-S-nitropyrimidine,2-butyl-4-chloro-5-11itro-6-aminopyrimidine,6-methoxyamino-S-nitro-4-chloropyrimidine,2-methyl-4-chloro-5-nitro-6aminopyrimidine,2,4-dichloro-5-nitro-6-aminopyrimidine,4-chloro-S-nitro-6-dimethylaminopyrimidine,4-chloro-S-nitro-6-methylaminopyrimidine,2-methyl-4-chloro-5-nitro-6-ethoxypyrimidine,4-chloro-5-nitro-6-methoxypyrimidine, 4-chloro-5-nitropyrimidine,4-chloro-5-nitro-6-ethoxypyrimidine,2-methoxy-4,6-dichloro-5-nitro-pyrimidine,4-chloro-5-nitro-G-diethylaminopyrimidine,2,6-dimethylthio-4-chloro-5-nitropyrimidine,2-methylthio-4,6-dichloro-S-nitropyrimidine,Z-methylthio-4-chloro-5-nitro-6-aminopyrimidine,2,4-dichloro-5-nitro-G-diethylaminopyrimidine,4-chloro-S-nitro--benzyloxypyrimidine,2,6-diamino-4-chloro-S-nitropyrimidine,4-chloro-5-nitro-G-benZyIamino-pyrimidine,4,-6-dichloro-5-nitropyrimidine, etc.

The compounds as mentioned above but substituted hydrogen, nitroso,aryldiazo, amino or acylamino for the nitro group at the 5-postion maybe also employed.

Examples of the reagent [II"] are the carboxylic acids bearing an aminogroup at the w-position, and their amides and alkyl esters. As the saidcarboxylic acids, there may be exemplified, Z-hydroxybutyric acid,3-hydroxybutyric acid, 3 hydroxyvaleric acid, 4-hydroxyvaleric acid,4-hydroxycaproic acid, S-hydroxycaproic acid, 4,5-dihydroxycaproic acid,5 hydroxyenantic acid, 3,5 dihydroxycaprylic acid, erythronic acid,threonic acid, and the like.

The reaction is usually eifected in a solvent (e.g. water, methanol,ethanol, dioxane). The reaction temperature is not limitative, and thereaction may be carried out at room temperature or while heating. Ifdesired, there may be employed an acid-eliminating agent such astertiary amine (e.g. triethylamine, pyridine), alkali metal carbonate,alkali metal hydroxide or alkali alkoxide.

The reaction in the step 2 is carried out by subjecting the compound[IIa] to reduction.

The reaction is particularly applicable to the compound [IIa] wherein Xis nitro, nitroso or aryldiazo.

Examples of the reduction procedure to be adopted are reduction with thecombination of a metal (e.g. iron, zinc, tin) and an acid (e.g.hydrochloric acid, formic acid), reduction with the combination of ametal (e.g. sodium, sodium amalgam, aluminum amalgam, zinc, iron) andwater or an alcohol, reduction with a sulfide (e.g. ammonium sulfide,ammonium hydrosulfide, sodium sulfide, sodium polysulfide, sodiumhydrosulfide, sodium sulfide, sodiup polysulfide, sodium hydrosulfide,hydrogen sulfide), re duction with sodium dithionite, sodiumhydrogensulfite or potassium hydrogensulfite, reduction withphenylhydrazine or hydrazine, reduction with the combination of titaniumtrichloride and hydrochloric acid, reduction with the combination ofhydroiodic acid and hypophosphorous acid, electrolytic reduction andcatalytic reduction. Of these, the last one is the most preferred.

For the catalytic reduction, the following catalyst may be used: e.g.platinum wire, platinum plate, platinum sponge, platinum black, platinumoxide, colloidal platinum, palladium sponge, palladium black, palladiumoxide, colloidal palladium, palladium-barium sulfate, palladium carbon,palladium-barium carbonate, palladium-silica gel, rhodium, iridium,colloidal rhodium, colloidal iridium, reduced nickel, oxidized nickel,Raney nickel, Urushibara nickel, nickel catalyst resulting frompyrolysis of nickel formate, reduced cobalt, Raney cobalt, Urushibaracobalt, reduced iron, Raney iron, reduced copper, Raney copper, Ullmanncopper, etc. The reduction is ordinarily effected in a solvent (e.g.water, formic acid, methanol, ethanol). During the reduction, thehydroxyamino, lower alkoxyamino, ar(lower)alkoxyamino or aryloxyaminogroup represented by R, in the compound [IIa] may be simultaneouslyreduced to amino.

The reaction in the step 3 is concerned with the conversion of X (thecompound [Ia] into NH-R (the compound [Ic]). This reaction isparticularly applicable to the compound [Ia] wherein X is amino, nitro,nitroso or aryldiazo. The reaction is carried out by treating thecompound [Ia] with an acylating agent, when X is not amino, whilereduction.

When the starting material in this step is the compound [Ia] wherein Xis amino, the treatment is effected by reacting the same with anacylating agent, usually in a solvent (e.g. Water, methanol, ethanol,formic acid, formamide) at room temperature or while heating. Examplesof the acylating agent are formic acid and reactive derivatives of loweralkanoic acid at its carboxyl group such as acid halide (e.g. acidchloride), acid anhydride, amide, azide and ester (e.g. methyl ester,ethyl ester). Examples of lower alkanoic acid are acetic acid, propionicia liid, butyric acid, valeric acid, isovaleric acid and the When thestarting material in this step is the compound [Ia] wherein X is nitro,nitroso or aryldiazo, the reaction is effected by reducing the same inthe presence of an acylating agent usually in a solvent (e.g. water,aqueous alcohol) at room temperature or while heating.

As the reduction procedure, there may be adopted a variety ofconventional procedures as mentioned in connection with the step 2.Particularly preferred is the catalytic reduction. Examples of theacylating agent are as defined above. Preferred is formic acid oranhydride of lower alkanoic acid.

In the course of the reaction in this step, the alkylthio, alkoxy oraralkoxy group or the halogen atom represented by R, and the alkoxy oraralkoxy group or the halogen atom represented by R may be convertedinto hydroxyl. When the hydroxyl groups in the hydroxylated alkylenegroup represented b R, are protected as alkylidene or aralkylidene, suchprotective group may be eliminated. Further, the free hydroxyl group inthe hydroxylated alkylene group represented by R, may be acylated tolower alkanoyloxy. Furthermore, the hydroxyamino, lower alkoxyamino,ar(lower)alkoxyamino or aryloxyamino group represented by R may bereduced to amino. All these side reactions are, however, within thescope of this invention, insofar as those do not block the preceding ofthe main reaction in this step.

In addition to the said reactions, various and numerous optionalreactions may be applied to the products in the steps 1 to 3.

One of such optional reactions is esterification, which may be carriedout by treating the products wherein the group represented by R ishydroxyl with an acylating agent in a conventional manner. Another ofsuch optional reactions is amidation, which may be effected by treatingthe products wherein the group represented by R is hydroxyl or itsfunctional derivative at the carboxyl group with an amine in aconventional manner. Further one of such optional reactions ishydrolysis which may be carried out by treating the products bearing oneor more hydrolyzable groups such as acylated hydroxyl, esterifiedcarboxyl or carbamoyl with an acidic or basic substance in aconventional manner so that the said hydrolyzable group is convertedinto the corresponding free group such as free hydroxyl, free amino orfree carboxyl.

The pyrimidine compounds [II] obtained as above may be converted intotheir salts such as metal salts (e.g. sodium salt, potassium salt,calcium salt), ammonium salt, amine salts (e.g. dimethylamine salt,trimethylamine salt, dicyclohexylarnine salt) and acid-addition salts,i.e. organic and inorganic acid-addition salts (e.g. hydrochloride,hydrobromide, sulfate, nitrate, phosphate, tartrate,

citrate), by per se conventional procedures.

The pyrimidine compounds [II] and their non-toxic salts are per souseful as hypocholesterolemic agents in addition to their utility as thestarting materials for production of purine compounds [Ia].

(1-1-2) RING CLOSURE FROM IMIDAZOLE NUCLEUS One of the procedures fallenin this category is representable by the following formulae:

r N N A" I R: HZNXJT BPXNAN.

rw-oo-n; fn-oo-R; 1 wherein R is amino or hydroxyl, R is hydrogen,amino, lower alkyl (e.g. methyl, ethyl, propyl), aryl such as phenyl orar(lower)alkyl such as phenyl(lower)alkyl (e.g. benzyl, phenethyl); Y iscyano, carbamoyl, amidino or -C(:=NH) (O-lower alkyl); and R R R R and Rare each as defined above.

The imidazole compound [III] is reacted with an imidic acid derivativeof the formula:

Rs-fii-RI NE [A] wherein R is hydrogen, lower alkyl (e.g. methyl, ethyl,propyl), aryl such as phenyl or ar(lower)alkyl such asphenyl(lower)alkyl (e.g. benzyl, phenethyl) and R is amino or loweralkoxy (e.g. methoxy, ethoxy, propoxy) or with an orthocarboxylic acidester of the formula:

in [13 wherein R is lower alkanoyl (e.g. acetyl, propionyl, butyryl) orlower alkyl (e.g. methyl, ethyl, propyl), R

12 and R are each lower alkyl (e.g. methyl, ethyl, propyl) and R is asdefined above and ammonia to give the purine compound [lb]. The reactionis usually carried out in a solvent such as water, methanol or ethanol,in case of the reagent [B], preferably in the presence of an acid suchas hydrochloric acid, sulfuric acid, acetic anhydride, ptoluenesulfonicacid or the like. When the starting compound is the imidazole compound[III: Y=carbamoyl], there is obtained as the product the purine compound[Ib: R =hydroxyl]. In other cases, the product is the purine compound[Ibz R =amino].

In the course of the said process, one or more of the substituentsrepresented by the symbols R and R may be influenced. Some examples ofsuch influence are as follows: conversion of the acylated or etherifiedhydroxyl group represented by R, into free hydroxyl, conversion of thehydroxyl or lower alkoxy group represented by R into amino, etc.

The starting imidazole compound [III] may be produced by variousmethods. For instance, 4-(4-cyano-5- aminol-imidazolyl)-4-deoxy-D-erythronic acid is prepared by reacting ethylN-(dicyanomethyl)-formimidate with 4-amino-4-deoxy-D-erythronic acid.Other starting compounds can be produced in the similar manner.

( 1-2) N-SUBSTITUTION The procedure represented by the followingformulae comes in this category:

wherein R is hydrogen, lower alkoxy (e.g. methoxy, ethoxy, propoxy),amino, lower alkylamino (e.g. methylamino, ethylamino, propylamino),di(lower)alkylamino (e.g. dimethylamino, diethylamino), ar(lower)alkylamino such as phenyl(lower)alky1amino (e.g. benzylamino,phenethylamino) or acylamino such as lower alkanoylamino (e.g.acetylamino, propionylamino, butyryiamino, octanoylamino) orbenzoylamino; R is hydrogen, amino, lower alkyl (e.g. methyl, ethyl,propyl) or aryl such as phenyl, R is hydrogen, amino, lower alkyl (e.g.methyl, ethyl, propyl) or aryl such as phenyl; R is lower alkylenepreferably having 2 to 6 carbon atoms (e. g. ethylene, trimethylene,propylene) substituted with one or more hydroxyls (but no hydroxyl groupbeing present at the carbon atom adjacent to the ring nitrogen atom)which are protected with lower alkyl (e.g. methyl, ethyl, propyl,isopropyl), ar(lower)alkyl such as phenyl(lower)alkyl (e.g. benzyl,phenethyl) or, when a pair of hydroxyls exist on the alkylene group,with lower alkylidene (e.g. ethylidene, propylidene, isopropylidene) orar(lower) alkylidene such as phenyl(lower)alkylidene (e.g. benzylidene);and Av is as defined above.

The purine compound [IV] is reacted witha lactone of the formula:

wherein R is as defined above to give the purine compound [Ic].

The reaction is executed ordinarily in a solvent (e.g.dimethylformamide, dimethylsulfoxide, xylene) in the presence of acondensing agent such as alkali metal (e.g. lithium, sodium, potassium),alkali metal hydride (e.g. lithium hydride, sodium hydride, potassiumhydride), alkaline earth metal hydride (e.g. calcium hydride, bariumhydride), alkali metal carbonate (e.g. sodium carbonate, potassiumcarbonate), alkaline earth metal carbonate (e.g.

calcium carbonate, magnesium carbonate), alkali metal bicarbonate (e.g.sodium bicarbonate, potassium bicarbonate), alkaline earth metalbicarbonate (e.g. calcium bicarbonate, magnesium bicarbonate), alkalimetal hydroxide (e.g. sodium hydroxide, potassium hydroxide), alkalineearth metal hydroxide (e.g. calcium hydroxide, magnesium hydroxide),alkali metal fluoride (e.g. cesium fluoride, potassium fluoride, lithiumfluoride) or alkali metal alkoxide (e.g. sodium ethoxide, potassiumt-butoxide) at a temperature from room temperature to the boilingtemperature of the reaction medium.

The starting purine compound [IV] is known or may be produced by variousconventional methods.

(2-1) HY DROLYSIS In this category, the procedure represented by thefollowing formulae is fallen:

wherein R is hydrogen, halogen (e.g. chlorine, bromine, iodine,fluorine), hydroxyl, mercapto, amino, lower alkyl (e.g. methyl, ethyl,propyl, isopropyl), aryl such as phenyl, lower alkoxy (e.g. methoxy,ethoxy, propoxy, isopropoxy), ar(lower)alkoxy such asphenyl(lower)alkoxy (e.g. benzyloxy, phenethyloxy) or lower alkylthio(e.g. methylthio, ethylthio, propylthio); and A, R R R R R R R R and Rare each as defined above.

The starting purine compound [V] wherein one or more hydrolyzable groupssuch as acylated hydroxyl, etherified hydroxyl, acylated amino,esterified carboxyl or carbamoyl are present is treated with an acidicor basic substance in an aqueous medium so as to obtain the objectivepurine compound [Id] in which at least one of the hydrolyzable groupspresent in the starting compound is hydrolyzed to make a free group suchas free hydroxyl, free amino or free carboxyl.

As the acidic substances, there may be employed hydrochloric acid,sulfuric acid, formic acid, acetic acid, benzoic acid or the like.Examples of the basic substance are sodium hydroxide, potassiumhydroxide, sodium carbonate, potassium carbonate, sodium methoxide,sodium ethoxide, potassium ethoxide, etc. There may be also used anacidic or basic ion-exchange resin. The reaction is ordinarily efiectedat a temperature from room temperature to the boiling temperature of thereaction medium.

In general, the hydrolysis proceeds equally by the use of an acidic orbasic substance. For conversion of the etherified hydroxyl group in Rinto free hydroxyl, the use of an acidic substance is essential.

As stated above, the said process is concerned with the hydrolysis ofone or more of the hydrolyzable substituents present on the purinenucleus or in the side chain. In the course of the process, however, anyother substituent may be influenced. Examples of such influence is asfollows: conversion of the halogen atom, mercapto or lower alkylthiogroup represented by R R or R into hydroxyl or lower alkoxy, etc.

(2-2) REDUCTION The conversion representable by the following formulaeis fallen in this category:

[V1] [19] BrC 0-35 14 wherein A, R1, R2, R3, R4, R5, R1, R2, R3,, R4 andR are each as defined above. 7

Thus, the purine compound [VI] wherein one or more reducible groups(including such groups convertible to hydrogen) are present is subjectedto reduction to give the purine compound [Ie] in which at least one ofthe reducible groups present in the starting compound is reduced.

For accomplishing the reduction, there may be adopted reduction with areducing agent, catalytic reduction, electrolytic reduction or the like.Examples of the reducing agent are the combination of a metal (e.g.iron, tin, zinc) with an acid (e.g. hydrochloric acid, acetic acid), thecombination of a metal (e.g. sodium, amalgamated sodium, amalgamatedaluminum, zinc, iron) with water or an alkanol (e.g. methanol, ethanol),a sulfide (e.g. ammonium sulfide, ammonium hydrosulfide, sodium sulfide,sodium polysulfide, sodium hydrosulfide, hydrogen sulfide), sodiumdithionite or sodium bisulfite, phenylhydrazinc or hydrazine, thecombination of titanium trichloride with hydrazine, the combination ofhydroiodic acid with hypophosphorous acid, etc. As the catalyst forcatalytic reduction, there may be exemplified platinum, platinum oxide,palladium, palladium oxide, palladium-carbon, palladium-barium sulfate,palladium-barium carbonate, palladium-silica gel, rhodium, iridium,ruthenium, nickel oxide, Raney nickel, Raney cobalt, reductive iron,Raney iron, reductive copper, Raney copper, Ullmann copper or zinc. Thereaction is ordinarily executed in a solvent suitably selected dependingon the kind of the reducing agent or the catalyst, and examples of thesolvent are water, acetic acid, methanol, ethanol and like.

(2-3 AMINATION One of the procedures in the category is representable bythe following formulae:

Z R11 12 I N\ \N/ N N B iL/ R N v11 rw-oo-m R2. \N N/ wherein R and Rare each hydrogen, lower alkyl (e.g. methyl, ethyl, propyl, isopropyl),ar(lower)alkyl such as phenyl(lower)alkyl (e.g. benzyl, phenethyl), acylsuch as lower alkanoyl (e.g. acetyl, propionyl, butyryl), phenyl-(lower)alkanoyl (e.g. phenacetyl) or benzoyl, hydroxyl, lower alkoxy(e.g. methoxy, ethoxy, propoxy), ar(lower) alkoxy such asphenyl(lower)alkoxy (e.g. benzyloxy, phenethyloxy) or aryloxy such asphenoxy; Z is halogen (e.g. chlorine, bromine), mercapto, loweralkylthio (e.g. methylthio, ethylthio, propylthio), lower alkenylthio(e.g. allylthio), lower alkylsulfonyl (e.g. methanesulfonyl,ethanesulfonyl), arylsulfonyl such as benzenesulfonyl or toluenesufonyl,ar(lower)alkylsulfonyl such as phenyl(lower) alkylsulfonyl (e.g.phenylmethanesulfonyl, phenylethanesulfonyl) or lower alkenylsulfonyl(e.g. allylsulfonyl); and R R R R R and R are each as defined above. Thereaction is carried out by treatment of the purine compound [VII] withan amine of the formula:

/NH R12 [D] wherein R and R are each as defined above, usually in asolvent (e.g. water, methanol, ethanol) while heating. The use of theamine [D] in excess to the purine compound [VII] is preferred. When thehydroxyl group(s) in the hydroxylated alkylene group represented by thesymbol R is acylated, the acylated hydroxyl group(s) may beconvertedinto hydroxyl simultaneously with the 1 proceeding of the aminationunder a strong reaction condition.

When the symbol R is lower alkoxy, it may be replaced by the group ofthe formula:

in the course of the reaction.

(2-4) ESTERIFICATION A typical procedure fallen in this category issubstantially representable by the following formulae:

wherein R is lower or higher alkyl (e.g. methyl, ethyl, propyl,isopropyl, octyl, decyl, heptadecyl); and A, R R R R and R are each asdefined above.

The reaction is effected by treating the purine compound [VIII] or itsfunctional derivative at the carboxyl group with a reagent of theformula:

wherein X is halogen (e.g. chlorine, bromine), hydroxyl,hydroxysulfonyloxy or lower alkoxysulfonyloxy (e.g. methoxysulfonyloxy,ethoxysulfonyloxy) and R is as defined above or a reagent of theformula:

wherein is lower alkylene (e.g. methylene, ethylene) in a solvent (e.g.methanol, ethanol, benzene, toluene, dimethylformamide, acetone, ether,tetrahydrofuran) at a temperature from room temperature to the boilingtemperature of the reaction medium.

As the functional derivative of the purine compound [VIII], there may beexemplified acid halide, acid azide, acid anhydride, amide and the like.

Depending on the kind of the reagent [E] or [F], there may be used anacidic or basic catalyst or condensing agent, of which examples are asfollows: hydrochloric acid, sulfuric acid, boron trifluoride,benzenesulfonic acid, p-toluene-sulfonic acid, hydrobromic acid, ferricchloride, aluminum chloride, zinc chloride,

N,N'-dicyclohexylcarbodiimide,

N-cyclohexyl-N'-morpholinoethylcarbodiimide,

N-cyclohexyl-N-(4-diethylaminocyclohexyl) carbodiimide,

N,N'-diethylcarbodiimide,

N,N'-diisopropylcarbodiimide,

N-ethyl-N'-(S-dimethylaminopropyl)carbodiimide,

N,N,-carbony1diimidazole,

N,N'-carbonyldi (Z-methylimidazole N,N-carbonyldipyrazole,

pentamethyleneketene-N-cyclohexylimine,

diphenyl-ketene-N-cyclohexylimine,

alkoxyacetylene,

1-alkoxy-l-chloroethylene,

tetraaalkyl phosphite,

2-ethyl-5- (N-sulfophenyl) isoxazolium hydroxide,

2 ethyl-7-hydroxybenzisoxazolium salt,

ethyl polyphosphate, isopropyl polyphosphate, phosphorus oxychloride,phosphorus trichloride, thionyl chloride, oxalyl chloride, stronglyacidic ion exchange resin, molecular sieve, alkali metal hydroxide,alkaline earth metal hydroxide, alkali metal carbonate, alkaline earthmetal carbonate, etc.

In the course of the above process, the acylated or etherified hydroxylgroup(s) in the symbol R may be converted into hydroxyl. I

2 5 ADMIDATION In this category, there is included the procedurerepresented by the following formulae:

wherein R is as defined above, usually in a solvent (e.g. water,methanol, ethanol, benzene, actone, dioxane, acetonitrile, chloroform,ethylene chloride, tetrahydrofuran, ethyl acetate, formic acid,pyridine) at a temperature from room temperature to the boilingtemperature of the reaction medium.

Examples of the functional derivatives of the purine compound [IX] areacid halide, acid anhydride, azide, ester and the like. Particularlypreferred are acid chloride, acid azide, alkylphosphoric acid mixedanhydride, benzylphosphoric acid mixed anhydride, halogenated phosphoricacid mixed anhydride, alkylcarbonic acid mixed anhydride, methyl ester,ethyl ester, cyanomethyl ester, p-nitrophenyl ester, pentachlorophenylester, proparg'yl ester, carboxymethyl thioester, pyranyl ester,methoxymethyl ester, phenyl thioester, etc. i

The amine may be used in free form or salt form such as hydrochloride orsulfate. In the latter case, the presence of a base in the reactionsystem is preferred. When desired, there may be used a condensing agentsuch as In the course of the reaction, the halogen atom, mercapto orlower alkylthio group represented by the symbols R R or R may bereplaced by the moiety R in the employed amine [G]. Further, theacylated hydroxyl group in the symbol R may be converted into hydrox'yl.(2-6) ACYLATION The procedure of the following formulae comes in the 17wherein R1, R3, R5, R1, R2,, R3, R4 and R5 are each as defined above.

In the above process, one or more substituents to be acylated areacylated. That is, the amino group(s) represented by the symbols R R andR may be converted into acylamino and also the hydroxyl group(s) in thesymbol R changed to acyloxy.

The reaction is carried out by treating the purine compound [X] with anacylating agent such as aliphatic carboxylic acid (e.g. acetic acid,propionic acid, butanoic acid, pentanoic acid, isopentanoic acid,pyvalic acid, 2-ethylbutanoic acid), aromatic carboxylic acid (e.g.benzoic acid, p-bromobenzoic acid, p-nitrobenzoic acid, phenylaceticacid, cinnamic acid) and heterocyclic carboxylic acid (e.g. nicotiincacid, isonicotinic acid) and their functional derivatives at thecarboXyl group such as their acid halide (e.g. acid chloride), acidanhydride, amide, azide and ester (e.g. methyl ester, ethyl ester,cyanomethyl ester, p-nitrophenyl ester, pentachlorophenyl ester,2,4,5-trichlorophenyl ester, proparg'yl ester, carboxymethyl thioester,pyranyl ester, methoxymethyl ester, phenyl thioester,N-hydroxysuccinimide), usually in a solvent (e.g. ether, acetone,dioxane, acetonitrile, chloroform, ethylene chloride, tetrahydrofuran,ethyl acetate, pyridine) while cooling, at room temperature or underheating. If necessary, there may be used a condensing agent such as orthe like. There may be also added a base such as alkali metal carbonate,trialkylamine or pyridine.

By selecting suitably the reaction conditions, it is possible toaccomplish optionally either one or both of the acylations of thehydroxyl group and of the amino group.

(2-7 ETHERIFICATI ON The procedure representable by the followingformulae is under this category:

' a. ib

wherein R is lower alkylene preferably 2 to 6 carbon atom (e.g.ethylene, trimethylene, propylene) substituted with one or morehydroxyls (but no hydroxyl group being present at the carbon atomadjacent to the ring nitrogen atom); R is lower alkylene preferablyhaving 2 to 6 carbon atoms (e.g. ethylene, trimethyl, propylene)substituted with one or more hydroxyls (but no hydroxyl group beingpresent at the carbon atom adjacent to the ring nitrogen atom) of whichat least one is protected with lower alkyl or ar(lower)alkyl or, when apair of hydroxyls exist on the alkylene group, with lower alkylidene orar(lower)alkylidene; and R R R and R are each as defined above.

The reaction is carried out byreacting the purine compound [XI] with areagent of the formula:

Ru /Y' R1: Y" wherein R is hydrogen or lower alkyl (e.g. methyl, ethyl,propyl, isopropyl), R is hydrogen, lower alkyl (e.g. methyl, ethyl,propyl, isopropyl), ar(lower)alkyl such as phenyl(lower)alkyl (e.g.benzyl, phenethyl) or aryl such as phenyl, and Y and Y" are each loweralkoxy (e.g. methoxy, ethoxy, propoxy, isopropoxy) or both represent anoxo group or with a reagent of the formula:

wherein R is lower alkyl (e.g. methyl, ethyl, propyl, isopropyl) orar(lower)alky1 such as phenyl(lower)alkyl (e.g. benzyl, phenethyl) andY' is hydroxyl or halogen (e.g. chlorine, bromine) in a solvent, usuallyat a temperature from room temperature to the boiling temperature of thereaction medium. In case of using the reagent [H], the addition of Lewisacid (e.g. hydrogen chloride, hydrogen bromide, perchloric acid, zincchloride, toluenesulfonic acid, di-p-nitrophenyl phosphate, phosphorusoxychloride, H-type ion exchange resin) to the reaction mediumispreferred. When the reagent [J] is employed, the incorporation of acondensing agent such as sulfuric acid, toluenesulfonic acid, sodiumhydrogen sulfite or silver oxide is recommended.

(2-8) OTHER CONVERSIONS In addition to the procedures as aboveillustrated, there may be adopted a variety of other conventionalprocedures for conversion of any substituent(s) present in the purinenucleus. For instance, the chlorine atom(s) present at the 2, 6 and/or8-positions are converted into hydroxyl by heating with formic acid inan aqueous medium. The chlorine atom(s) present at the 2, 6 and/ or8-positions are converted into mercapto by reacting with thiourea in asolvent, followed by treatment with an alkali. The chlorine atom(s) atthe 2, 6 and/or 8- positions can be converted to hydroxyamin'o byreacting with hydroxylamine. The chlorine atom(s) at the 2, 6 and/or 8-ositions are converted into lower alkoxy by reacting with alkali metallower alkoxide (e.g. sodium methoxide, sodium ethoxide, potassiumethoxide). The mercapto group(s) at the 2, 6 and/or 8-positions may bechanged to lower alkylthio by reacting with lower alkyl halide (e.g.methyl chloride, methyl iodide, ethyl chloride) in the presence of abase. The amino group(s) at the 2, 6 and/or 8-positions may be convertedinto hydroxyl by reacting with nitrous acid.

The purine compounds [I] obtained as above may be converted into theirsalts such as metal salts, ammonium salts, amine salts and acid-additionsalts by per se conventional procedures.

The purine compounds [I] and their salts generally exhibit markedhypocholesterolemic activity. The test results on the standard compound,i.e. 4-(6-aminopurin-9- yl)-4-deoxy-D-erythronic acid, are shown below.

1. TEST METHOD fied with hydrochloric acid or an aqueous suspension withcarboxymethyl cellulose. As the positive control, thyroxin was orallyadministered at a dose of 0.05 mg. peranimal.

Animal Administration route LDu(mg./kg.)

.... Subcutaneous 2, 700 Intraperitoneal 1,.000-2000 ml 4,000

Thus, the purine compounds [I] and their non-toxic salts are useful asthe therepeutic agents in the treatment of atherosclerosis. Thepyrimidine compounds [I1] and their non-toxic salts exhibit the similaractivity and can be subjected to the same use.

The purine compounds [I] and the pyrimidine compounds [II], and theirnon-toxic salts are stable to heat and light, and they can beadministered by the conventional methods, the conventional types of unitdosages or with the conventional pharmaceutical carriers to produce ahypocholesterolemic activity in human beings. Thus, they can be used inthe form of pharmaceutical preparation, which contain them in admixturewith a pharmaceutical organic or inorganic carrier material suitable forenteral or parenteral applicaitons. Oral administration by the use oftablets, capsules or in liquid form such as suspensions, solutions oremulsions, or injectional application is particularly advantageous. Whenformed into tablets, the conventional binding and disintegrating agentsused in therapeutic unit dosages can be employed. Illustrative ofbinding agents there can be mentioned glucose, lactose, gum acacia,gelatin, mannitol, starch paste, magnesium trisilicate and talc.Illustrative of disintegrating agents there can be mentioned cornstarch, keratin, colloidal silica and potato starch. When administered,as liquidsthe conventional liquid carriers can be used.

The dosage or therapeutically effective quantity of the purine compounds[I] and the pyrimidine compounds [II], and their salts for human beingscan vary over wide limits such as that of about to 1000 milligrams/dayfor adult. The upper limit is limited only by the degree of eflectdesired and economic considerations. For oral administration it is toemploy from about 5 to 30 milligrams of the therapeutic agent per unitdosage. For injectional use,-the active ingredient may be employedfrom 1. to 10 mg. per unit dosage. Of course, the dosage of theparticular therapeutic agent used can vary considerably, such as the ageof the patient and the degree of therapeutic effect desired. By the termpharmaceutical carrier it is intended to include non-therapeutic"materials which are conventionally used with unit dosage and includesfillers, diluents, binders lubricants, disintegrating agents andsolvents. Of course, it is possible to administer the noveltherapeutics, i.e. the pure compounds, without the use of apharmaceutical carrier.

Practical and presently-preferred embodiments of this invention areillustratively shown in the following Examples.

Example 1 Fresh Lentinus edodes (10 kg.) was triturated, and aqueousmethanol (20 l.) was added thereto. The mixture was subjected toextraction of the active component under reflux for 3 hours. The aboveoperation was repeated twice. The extracts were combined together,concentrated under reduced pressure to 6 l. and shaken with ether. Thewater layer was separated, diluted with water 20 l.) and passed througha strongly acidic ion-exchange resin [H-type Amberlite IR-l20 (tradename) The resin was washed with water and then eluted with 2%- ammoniawater. The eluate was concentrated under reduced pressure andlyophilized to obtain brown powder (60 g.). The powder was dissolved inwater (400 ml.) and, after elimination of insoluble materials, thesolution was passed through a strongly acidic ion-exchange resin[H-type, Dowex 50X2 (trade name)]. The resin was washed with Water andthen eluted gradiently wtih 1 N to 4 N hydrochloric acid solutions. Thefractions which aiforded a maximum absorption aroundt 260 my in theultraviolet absorption spectrum were combined together and lyophilizedto obtain white powder. The powder was dissolved in water, and thesolution was again passed through a strongly acidic ion-exchange resin[H-type, Dowex 50X2 (trade name)]. The resin was washed with water andeluted with 2% ammonia water, and the eluate was lyophilized to giveyellowish white powder. The powder was dis solved in 0.1 M pyridineacetate bulfer. The solution was passed through a strongly acidicion-exchange resin [H- type Dowex 50X2 (trade name)] pretreated with 0.1M pyridine acetate buffer. The resin was then eluted with 0.1 M pyridineacetate butter. The eluate was divided into fractions of each 25 ml. Thefractions which afforded a maximum absorption arounnd 260 m, in theultraviolet absorption spectrum were combined together and lyophilizedto give crude crystals, which were recrystallized from water to produceabout 250 mg. of the novel purine compound [I] as pure crystals. M.P.279 C. (decomp.).

Example 2 Dried Lentinus edodes (2.5 kg.) was crumbled, and 80% aqueousmethanol (20 l.) was added thereto. Then, the mixture was treated as inExample 1 to produce about 265 mg. of the purine compound [I'] as purecrystals.

Example 3 Dried Lentinus edodes (50 kg.) was crumbled and extracted with60% aqueous methanol (400 1.). The extract was concentrated underreduced pressure, and the concentrate was passed through a stronglyacidic ion-exchange resin [H-type Amberlite IR- (trade name)]. The resinwas washed with Water and eluted with 2% ammonia water. The eluate wasconcentrated to give the concentrate (2150 g.). The concentrate (10 g.)was dissolved in acetic acid-ammonium hydroxide buffer (pH 5, 0.1 N asacetic acid) (80 ml.) and passed through a strongly basic ion-exchangeresin [acetic acid-type Amberlite IRA-400 (trade name)] pretreated withthe same butler as above. The resin was washed with the same bulfer asabove and eluted with 0.5 N acetic acid. The fractions showing a maximumabsorption around 260 my in the ultraviolet absorption spectrum arecollected, concentrated under reduced pressure and dried in vacuo togive the purine compound [I] (120 mg.) as pure crystals.

Example 4 The concentrate (20 g.) obtained in the course of theprocedure as in Example 3 was dissolved in water (200 ml.) and passedthrough a strongly basic ion-exchange resin [acetic acid-type AmberliteIRA-400 (trade name) The resin was washed with water, 0.03 N acetic acidand 0.3 N acetic acid in order and eluted with 0.5 N acetic acid. Thefractions showing a maximum absorption around 260 my. in the ultravioletabsorption spectrum were collected, concentrated under reduced pressureand dried in vacuo to give the purine compound [I'] (100 mg.) as purecrystals.

Example 5 The concentrate (200 g.) obtained in the course of theprocedure as in Example 3 was dissolved in water (1 l.) and passedthrough a strongly basic ion-exchange resin [acetic acid-type AmberliteIRA-400 (trade name)]. The resin was washed with water and aceticacid-ammonium hydroxide buffer (pH 5, 0.1 N as acetic acid) in order andeluted with 0.5 N acetic acid. The fractions showing a maximumabsorption around 260 m in the ultraviolet absorption spectrum werecollected, concentrated under reduced pressure and dried in vacuo togive the purine compound [1'] (2.80 g.) as pure crystals.

Example 6 Dried Lentinus edodes (50 kg.) was extracted with water (400l.) at room temperature for 24 hours. The extract was passed through astrongly acidic ion-exchange resin [H-type Amberlite IR-120 (tradename)]. The resin was washed with water and eluted with 2% ammoniawater. The eluate was concentrated to give the concentrate (2300 g.).The concentrate (200 g.) was treated as in Example 5 to give the purinecompound [I] (3.0 g.) as pure crystals.

Example 7 Dried Lentinus edodes (50 kg.) was extracted with 50% aqueousmethanol (400 1.). The extract was passed through a strongly acidicion-exchange resin [H-type Amberlite IR-120 (trade name)]. The resin wasWashed with water and eluted with 2% ammonia water. The eluate wasconcentrated to give the concentrate (2200 g.). The concentrate (200 g.)was treated as in Example 5 to glve the purine compound [I'] (2.9 g.) aspure crystals.

Example 8 (A) Triethylamine (400 mg.) and formamidine acetate (250 mg.)were added to a suspension of 4-(5,6-diamino- 4 pyrimidinylamino)4-deoxy-2,3-O isopropylidene-D- erythronic acid (500 mg.) in MethylCellosolve (10 ml.). The mixture was heated under reflux for 20 minutes.The solvent was removed from the reaction mixture under reducedpressure. The residue was dissolved in water and the aqueous solutionwas adjusted to pH 3 with dilute hydrochloric acid. Precipitatedcrystals were collected by filtration and washed with water to give4-(6-aminopurin-9- yl)-4-deoxy-2,3-O-isopropylidene-D-erythronic acid(250 mg.) M.P. 214 C. (recrystallized from water).

(B) A solution of 4-(4,5-diamino-4-pyrimidinylamino)-4-deoxy-2,3-O-isopropylidene-D-erythronic acid 120 mg.) in 90% formicacid (3 ml.) was heated under reflux for an hour. After cooling, theformic acid was removed from the reaction mixture by evaporation underreduced pressure. To the residue was added water, and the solvent wasagain evaporated under reduced pressure. To the residue was added asmall amount of water, and precipitated crystals were collected byfiltration, washed with water and then methanol and recrystallized fromwater to give pillars (75 mg.) of 4-(6-amino-5-formamido-4-pyrimidinylamino)-4-deoxy-D-erythronic acid. M.P. 190 C. (decomp.). Asolution of 4(6-amino-5-formamido-4-pyrimidinylamino)-4-deoxy-D-erythronic acid (0.50 g.) in N sodiumhydroxide (5 ml.) was heated for 10 minutes in a boiling water bath.After cooling, N hydrochloric acid (5 ml.) was added to the reactionmixture and precipitated crystals were collected by filtration. Thesecrystals were washed with water and then methanol to give4-(6-aminopurin-9-yl)-4-deoxy-D-erythronic acid (0.34 g.). M.P. 279 C.(decomp.). [a] =+30 (c.=0.93, dimethylsulfoxide).

UV spectrum: 533 261 my (e=14,700).

(C) A solution of 4-(5,6-diamino-4-pyrimidinylamino)- 4-deoxy-2,3-Oisopropylidene-D-erythronic acid 200 mg.) in a mixture of 98% formicacid (1 ml.) and formamide (1 ml.) was heated for 30 minutes underreflux. To the reaction mixture was added ethanol, and precipitatedcrystals were collected by filtration. These crystals were dissolvedinto water, and the aqueous solution was treated with carbon powder andfiltered. The filtrate was condensed, and methanol was added to theresidue. Precipitated crystals were collected by filtration and washedwith methanol to give 4-(6-amino-purin-9-yl)-4-deoxy-D-erythronic acid(40 mg.). M.P. 279 C. (decomp.).

The above prepared 4-(6-aminopurin-9-yl)-4-deoxy-D- erythronic acid(3.80 g.) was dissolved in N sodium hydroxide solution (17 ml.). warmedat 40 C. and filtered. Ethanol (30 ml.) was added to the filtratedropwise. Precipitated crystals were collected by filtration and washedwith ethanol to give sodium 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate(3.40 g.). M.P. 272 C. (decomp.).

UV spectrum: x133; 261 m .=14,700

The above prepared 4-(6-aminopurin-9-yl)-4-deoxy-D- erythronic acid (500mg.) was dissolved in 1 N hydro chloric acid (10 ml.). The solution wascondensed under reduced pressure. Ethanol was added to an oily residueand the mixture was allowed to stand. Precipitated crystals werecollected and washed with ethanol to give 4- (6aminopurin-Q-yl)-4-deoxy-D-erythronic acid hydrochloride (380 mg.). M.P.198 to 201 C.

The above prpeared 4-(6-aminopurin-9-yl)-4-deoxy-D- erythronic acid (500mg.) was dissolved in 30% ammonia water (50 ml.). The solution wasconcentrated under reduced pressure and the concentrate was dissolved inethanol. The solution was allowed to stand to give crystals. Thecrystals were washed with ethanol to give 4-(6- aminopurin 9yl-4-deoxy-D-erythronic acid ammonium salt (340 mg.). M.P. 265 to 267 C.(decomp.).

(D) To a suspension of 4-(S-amino-6-chloro-4-pyrimidinylamino)4-deoxy-2,3-O-isopropylidene-D-erythr0nic acid (810 mg.) in triethylorthoformate (25 ml.), was added dropwise conc. hydrochloric acid (0.36ml.). The mixture was stirred for 3 hours at room temperature. Thereaction mixture was condensed under reduced pressure and the residuewas dissolved in dichloromethane. An insoluble substance was filteredoff, the filtrate was evaporated under reduced pressure and the residuewas dis solved in isopropyl ether. Rubbing the inside of the reactionvessel, precipitated crystals were collected by filtration to give4-(6-chloropurin-9-yl)-4-deoxy-2,3-O-isopropylidene-D-erythronic acid(640 mg.). Yield, 76% M.P. 150 C. (decomp.) (Recrystallized fromisopropyl ether). [a] =+5l.6 C. (c.=0.835, methanol).

(E) A solution of 4-(5-amino-6-chloro-4-pyrimidinylamino)4-deoxy-2,3-O-isopropylidene-D-erythronic acid (700 mg.) in formic acid(15 ml.) was heated at C. for 2 hours. The reaction mixture wasevaporated under reduced pressure. The residue was dissolved in amixture of 10% sodium hydroxide solution (3 ml.) and water (5 ml.). Thereaction mixture was heated on a water bath for 15 minutes and, aftercooling, neutralized with hydrochloric acid. The resultant mixture waspassed through a column containing a strong acidic ion-exchange resin[H-type, Amberlite IR B (trade name)] (40 ml.). The column was washedwith water till the eluate became neutral and thereafter eluted with 2%ammonia. The eluate was evaporated under reduced pressure, and

the residue was recrystallized from aqueous ethanol to give slightlybrown plates (280 mg.) of 4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronicacid. This substance sintered at about 85 C., expanded at 100 to 105 C.and then melted around 185 C. Yield, 48%. I

(F) -To a suspension of 4-(5-amino-6-chloro-4-pyrimidinylarnino)-4-deoxy-D-erythronic acid (6.76 g.) in triethylorthoformate (200 ml.), conc. hydrochloric acid (3 ml.) was added, andthe mixture was stirred at room temperature for 24 hours. The reactionmixture from which an insoluble substance was removed, was condensedunder reduced pressure. To the residue was added ethyl acetate, andinsoluble crystals were collected by filtration to give4-(6-chloropurin-9-yl)-4-deoxy-D-erythronic acid. The filtrate wascondensed under reduced pressure, and the residue was added with ethylacetate. An insoluble substance was collected by filtration to give thesame objective substance. The total yield is 6.71 g. This substance wasrecrystallized from isopropanol to give the isopropan01 adduct. M.P. 110C. (decomp.). [a] =+34 (c. =0.54 l, dimethylsulfoxide UV spectrum: x21}? EC 220 m, =17 g); 1 m 270 m (e=15,000); x23; 234 m g 276.5 mp($13,800); tags New 234.5 mp ($23,100); was 277 m4 ($15,000

(H) A solution of4-(5-acetamide-6-amino-4-pyrimidinylamino)-4-deoxy-2,3-0-isopropylidene-D-erythronicacid (1.5 g.) in N sodium hydroxide solution (15 ml.) was heated in aboiling water bath for 1.5 hours. The reaction mixture was allowed tostand to cool, neutralized with N hydrochloric acid and then condensedunder reduced pressure to volume. Precipitated crystals were collectedby filtration and washed with water and then methanol to give4-(6-amino-8-methylpurin-9-yl) 4 deoxy-2,3-O-isopropylidene-D-erythronicacid (0.7 g.). M.P. 265 C. (decomp.).

('I) To a solution of4-(5,6-diarnino-4-pyrimidinylamino)-4-deoxy-2,3-O-isopropylidene-D-erythronicacid (960 mg.) in an ethanol solution (20 ml.) of metallic sodium (180mg.), carbon disulfide (1 ml.) was added. The mixture was heated underreflux for 4 hours. From the reaction mixture, the ethanol was removedunder reduced pressure. A small amount of water was added to theresidue. The aqueous solution was adjusted to pH 3 with dilutehydrochloric acid. Precipitated crystals were collected by filtrationand washed with methanol to give 4-(6-amino- 8-mercapto-9H-purin-9-yl) 4deoxy-2,3-O-isopropylidene-D-erythronic acid (650 mg). M.P. 203 C.(decomp.).

(I A solution of4-(2-chloro-5,6-diamino-4-pyrimidinylamino)-4-deoxy-2,3-O-isopropylidene-D-erythronicacid (1.1 g.) in formic acid (5 ml.) was heated with reflux for 3 hours.The formic acid distilled off under reduced pressure. N sodium hydroxidesolution (14 ml.) was added to the residue and heated with reflux for 7hours. After cooling, the reaction mixture was adjusted to pH 2.5 withhydrochloric acid. Precipitated crystals were collected by filtration,decolored by carbon powder and recrystallized from water to give 4(2-hydroxy-6-aminopurin-9-yl)-4- .=13,400 mag 248 mp. (e=6,200), 286 mp(K) 4-(2-hydro-xy 5formamido-6-amino-4-pyrimidinylamino)-4-deoxy-D-erythronic acid preparedfrom 4- (2-ch1oro-5,6-diamino-4-pyrimidinylamino) 4 deoxy-2,3-O-isopropylidene-D-erythronic acid 1.1 g.) and formic acid (5 ml.)was added to N sodium hydroxide solution (14 ml.), and the mixture washeated with reflux for 7 hours. After cooling, the reaction mixture wasadjusted to pH 2.5 with hydrochloric acid. Precipitated crystals werecollected by filtration, decolored by carbon powder and recrystallizedfrom water to give 4-(2-hydroxy-6- aminopurin-Q-yl)-4-deoxy-D-erythronicacid (670 mg.). M.P. over 300 C. (decomp.).

(L) A mixture of 4-(5,6-diamino-4-pyrimidinylamino)-4-deoxy-2,3-O-isopropylideue-D-erythronic acid (0.5 g.) and urea (0.41g.) was heated at 170 to 180 C. on an oily bath for 25 minutes andwashed with a small amount of ethanol. The excess urea was removed, andthe insoluble substance was dissolved in a small amount of water. Theaqueous solution was adjusted to pH 3 with 10% hydrochloric acid to givecrystals. These crystals were collected by filtration and washed withwater to give 4-(6-amino-8-hydroxypurin-9-yl) 4 deoxy-D-erythronic acid(150 mg). M.P. 215 to 217 C. (decomp.).

UV spectrum: A

max

210 my, 270 my.

for an hour. The formic acid was distilled off. The residue wasdissolved in 1 N sodium hydroxide (6 ml.) and the solution was heatedrefiuxively for 2 hours. After cooling, the reaction mixture was passedthrough a column packed with a basic ion-exchange resin [Amber-liteIRA-400 (trade name)] (50 ml.). The resin was washed with Water till thewashings became neutral and eluted with 0.5 N formic acid. The eluatewas concentrated under reduced pressure and the residue wasrecrystallized from isopropanol to give4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronic acid (430 mg). Thissubstance expanded at to C. and then melted around 185 C.

(O) A mixture of methyl4-(5,6-diamino-4-pyriminylamino)-4-deoxy-D-erythronate (0.27 g.) informamide (2.0 ml.) was heated for 20 minutes at 160 C. on an oil bath.The formamide was distilled olf from the reactionmixture under reducedpressure. The residue was dissolved in methanol (20 ml.) under heating,and the solution was treated with carbon powders and filtered. Themethanol was removed by filtration under reduced pressure and theresidue was washed with a small amount of methanol to give methyl4-(6-aminopurin-9-yl)-4-deoXyD-erythronate (0.10 g.). M.P. 231 C.(decomp.).

(P) To a solution of ethyl4-(S,6-diamino-4-pyrimidinylamino)-4-deoxy-D-erythronate (400 mg.) inMethyl Cellosolve (5 ml.) was added tormamidine acetate (160 mg), andthe mixture was heated for 20 minutes at C. The solvent was removed byfiltration and the residue was dissolved in 50% ethanol (20 ml.). To thesolution, was added to weakly basic ion-exchange resin- [Amberlite IR-45(trade name)] (2.0 g.) and the mixture was stirred for about an hour andthen filtered. The filtrate was condensed under reduced pressure, andthe residue was added with a small amount of ethanol and allowed tostand. Precipitated crystals were collected and washed with ethanol togive ethyl 4-(6-aminopurin-9-yl)- 4-deoxy-D-erythronate (110 mg.). M.P.160 C.

(Q) A mixture of 4-(5-formamido-6-amino-4-pyrimidinylamino)4-deoXy-D-erythronic acid (0.06 g.) and formamide (2.0 ml.) was heatedfor 20 minutes at 160 C. on an oil bath and concentrated under reducedpressure. The residue was dissolved in methanol and an insolublesubstance was filtered ofi. The filtrate was concentrated to yieldcrystals and thus obtained crystals were washed with methanol to givemethyl 4-(6-amino-purin-9-yl)-4- deoxy-D-erythronate (0.03 g.). M.P. 231C. (decomp.).

In the similar manner, there are obtained the following compounds:

methyl 4-(6-aminopurin-9-yl)4-deoxy-D-erythronate [M. P. 231 C.(decomp.)];

ethyl 4- (-6-aminopurin-9-yl)-4-deoxy-D-erythronate [M.P. 159 to 160 C.(decomp.)J;

4- (6-aminopurin-9-yl) -4-deoxy-D-erythronamide [M.P. 264 to 268 C.(decomp.)]g

4-(6-amino-8-methylpurin-9-yl)-4-deoxy-D-erthronic acid [M.P. 281 C.(decomp.)1;

4- 6-amino-8-mercaptopurin-9-yl) -4-deoxy-D-erythronic acid [M.P. 265 to268 C. (decomp.)];

methyl4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-isopropylidene-D-erythronfiate [M.P.180 to 181 C.]; 4-(6-aminopurin-9-yl)-4-deoXy-2,3-O benzylidene-D-erythronic acid [M.P. 198 to 199 C. (decomp.)1;4-(Z-amino-6-hydroxypuri11-9-yl)-4-deoxy-D-erythronic acid [M.P. 223 C.(decomp.)]; 4- (6-hydroxypurin-9-yl -4-deoxy-D-erythronamide [M.P. 247C. (decomp.)]; 4-(6-ethylaminopurin-9-yl)-4-deoxy-D-erythronic acid[M.P. 242 to 243 C. (decomp.)J; 4-(6-diethylaminopurin-9-yl)-4-deoxy-D-erythronic acid [hydrochloride;M.P. 187 C. (decomp.)]; 4-(6-hydroxyaminopurin-9-yl)-4-deoxy-D-erythronic acid [M.P. 206.5 C.(decomp.)]; 4-(6-benzylaminopurin-9-yl)-4-deoxy-D-erythronic acid [M.P.206 to 206.5 C. (decomp)]; 4-(6-amin0purin-9-yl)-4-deoxy-L-threonic acid[M.P. 291

to 293 C. (decomp.)]; ethyl4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronate [M.P. 212 C. (decomp.)];4-(6-methylthiopurin-9-yl)-4deoxy-D-erythronic acid [melted at 85 C.,solidified at 90 C. and decomposed at 260 C.];4-(purin-9-yl)-4-deoxy-D-erythronic acid [M.P. 230 C.

(decomp.)1;N-ethyl-4-(6-aminopurin-9-yl)-4-deoxy-2,3-O-isopropylidene-D-erythronamide[M.P. 178 to 179 C. (decomp) N-ethyl-4- 6-aminopurin-9-yl)-4-deoxy-D-erythronamide [M.P. 166 to 168 C. (decomp.)];N,N-diethyl-4-(6-aminopurin 9=yl)-4-deoxy-D-erythronamide [M.P. 192 to193 C. (decomp.)];4-(6-ethylaminopurin-9-yl)-4-de0xy-2,3-isopropylidene- D-erythronicacid; 4-(6-methoxypurin-9-yl) 4deoxy-D erythronic acid (sodium salt;vesicat'ed at 168 to 170 C. and colored at 220 to 230 C. withvesication]; 4-(2,6-dihydroxypurin-9-yl)-4-deoxy-D-erythronic acid [M.P.204 to 206 C. (decomp.)];4-(2-methyl-6-aminopurin-9-yl)-4deoxy-D-erythronic acid;4-(6-butylaminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(6,8-dihydroxypurin-9-yl)-4-deoxy-D-erythronic acid;4-(2,6-diaminopurin-9-yl)-4-deoxy-D-erythronic acid;4(6,8-diaminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(2-aminopurin-9-yl)-4-deoxy-D-erythronic acid;

4-(8-aminopurin-9-yl)-4-deoxy D-erythronic acid, 4-(6- aminopurin-9-yl-4-deoxy-2, 3-O-isopropylidene-D- threom'c acid [M.P. 223 C. (decomp.)1;and

methyl 4- 6-aminopurin-9-yl) -4-deoXy-D-threonate [M.P. 211 to 212 C.(decomp.)], etc.

Example 9 (A) To a solution of 4-(6-amino-5-nitro-4-pyrimidinylamino) 4deoxy-2,3-0=isopropylidene-D erythronic acid (3.13 g.) in formic acid(45 ml.), 10% palladiumcarbon (0.4 g.) was added, and the mixture wassubjected to the catalytic hydrogenation. After completion of thereaction the catalyst was filtered off, and the formic acid wasevaorated under reduced pressure. The residue was dissolved in water,and the solvent was evaporated under reduced pressure. To the residuewas added a small amount of water, and precipitated crystals werecollected by filtration. These crystals were washed with methanol togive pillars (2.37 g.) of 4-(6-amino-5-formamido-4-pyrimidinylamino)-4deoxy-D-erythronic acid. M.P. 190 C. (decomp.). Asolution of 4-(6-amino-5-formamido-4-pyrimidinylamino-4-deoxy-D-erythronic acid (0.50 g.) in N sodiumhydroxide (5 ml.) was heated in a boiling water bath for 10 minutes.After cooling, N hydrochloric acid (5 ml.) was added to the reactionmixture. Precipitated crystals were collected by filtration and washedwith water and then methanol to give 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronic acid (0.34 g.). M.P. 279 C. (decomp.). [a] ==+30(c.=0.93, dimethylsulfoxide).

UV spectrum: 33 261 mu 6:14.300

Ammonium salt: M.P. 265 to 267 C. (decomp.). Sodium salt; M.P. 272 C.(decomp.). Hydrochloride: M.P. 198 to 201 C.

(B) To a solution of 4-(6-amino-S-nitro-4-pyrimidinylamino)-4-deoxy-2,3G isopropylidene-D-erythronic acid (1.0 g.) in 98% formic acid (10 ml.),a solution of sodium dithionite (1.5 g.) in water (5 ml.) was dropwiseadded. After completion of the addition, the mixture was heated withreflux for an hour. The formic acid was distilled off from the reactionmixture under reduced pressure. The residue was dissolved in water, andthe solvent was evaporated under reduced pressure. To the residue, therewas added N sodium hydroxide (10 ml.) to make alkaline, and the solutionwas heated in a boiling water bath for 10 minutes. The reaction mixturewas condensed to a half volume and allowed to cool. Precipitatedcrystals were collected by filtration to give sodium4-(6-aminopurin-9-yl)-4-deoxy-D-erythronate (0.12 g.). This substancewas dissolved in water. The aqueous solution was adjusted to pH 3, andprecipitated crystals were collected by filtration to give4-(6-aminopurin-9-yl)-4-deoxy-D-erythronic acid. M.P. 279 C. (decomp.).

(C) To a solution of 4-(2-amino-5-nitro-6-hydroxy-4- pyrimidinylamino) 4deoxy 2,3 O isopropylidene- -D-erythronic acid (6.1 g.) in 98% formicacid ml.), there was added palladium black (0.5 g.), and the mixture wassubjected to catalytic hydrogenation at room temperature underatmospheric pressure. After the absorption of hydrogen gas stopped, thecatalyst was removed by filtration, and the filtrate was heated for anhour under reflux. From the reaction mixture, the formic acid wasremoved by distillation under reduced pressure. The residue wasdissolved into a small amount of water, and the solvent was distilledoff under reduced pressure. The residue was dissolved into 0.5 N sodiumhydroxide solution (90 ml.), and the solution was heated for an hourunder reflux and condensed under reduced pressure to about A volume.

The concentrate was acidified by dilute hydrochloric acid and allowed tostand. Precipitated crystals were collected by filtration, washed withWater and then recrystallized from water to give4-(2-amino-6-hydroxypurin-9-yl)- 4-deoxy-D-erythronic acid (1.45 g.).M.P. 223 C. (decomp.).

UVspe'ctrum: 332 253 mp .=12,400 3 270 mp. (e=9,100); xgggf 270 mu(.=10,s00); x2 35 m 255 mp (e=12,000); 16. 25 280 my (e=7,900).

(D) A solution of ethyl 4-(5-nitro-6-amino-4-pyrimidinylamino) 4'- deoxy2,3 O dibenzoyl-L-threonate (2.5 g.) in 90% formic acid (40 ml.) wassubjected to catalytic hydrogenation in the presence of palladium carbonat room temperature, after which the palladium carbon was filtered off.The filtrate was condensed under reduced pressure, and N sodiumhydroxide solution (45 ml.) and ethanol (45 ml.) were added thereto. Themixture was heated for 30 minutes under reflux and then coudensed underreduced pressure. The residue was dissolved in water, and the aqueoussolution was adjusted to pH 3 by 10% hydrochloric acid. Precipitatedcrystals were collected by filtration and washed with water and thenethyl acetate to give 4-(6-amiuopurin-9-yl)-4-deoxy-L- threonic acid(0.54 g.). M.P. 291 to 293 C. (decomp.) (recrystallized from 10% aceticacid). [u] =95.0 (c.=0.505, dimethylsulfoxide) UV spectrum: A3 3 262 my.=14,eoo use 260 my (6 14,200); 763,33 MOE 262.5 mp. (e=14,500).

(E) A solution of4-(5-nitro-6-methoxy-4-pyrim-idinylamino)-4-deoxy-D-erythronic acid (2.4g.) in 90% formic acid (60 ml.) was subjected to catalytic hydrogenationin the presence of palladium black (500 mg), after which the palladiumblack was filtered ed. The filtrate was heated with reflux for 2 hoursand the formic acid was distilled oif under reduced pressure. N sodiumhydroxide solution (25 ml.) was added to the residue and the mixture washeated under reflux for 30 minutes. After cooling, the reaction mixturewas absorbed on an ion-exchange resin [OH type, Amberlite IRA 400 (tradename)] (400 ml.) and the resin was Washed with water till the washingsbecame neutral. The eluate with 0.5 N formic acid Was concentrated withreflux to give a solid (1.2 g.), which was recrystallized fromisopropanol to afford 4-(6-hydroxypurin 9 yl) 4 deoxy D erythronic acid.This substance sintered at about 85 C., expanded at 100 to 105 C. andthen melted around 185 C.

(F) To a solution of4-(5-nitro-6-amino-4-pyri-midinylamino)-3-hydroxy-Dbbutyric acid (2.0g.) in 90% formic acid (30 ml.), was added palladium-carbon (200 mg.).The mixture was subjected to catalytic hydrogenation at room temperatureunder atmospheric pressure. After the absorption of hydrogen gasstopped, the catalyst was removed by filtration, and the filtrate washeated for 30 minutes under reflux. From the reaction mixture, thesolvent was removed by distillation under reduced pressure. The residuewas dissolved into a small amount of water, and the solvent wasdistilled 01f under reduced pressure. In order to remove the formicacid, there were repeated three times the procedures of dissolution ofthe residue in water and distillation of the solvent. The residue wasdissolved into N sodium hydroxide solution (20 ml), and the solution washeated for 30 minutes on a water bath. After cooling, the reactionmixture was neutralized by 10% hydrochloric acid, and precipitatedcrystals were collected by filtration, washed with water and then driedto give 4-(6-aminopurin 9-yl)-3-hydroxy-DL butyric acid (1.5 g.). M.P.290 to 291 C. (decomp.) (recrystallized from 10% acetic acid).

(G) A solution of 4-(5-nitro-6-pyrimidinylamino-4-deoxy-D-erythronicacid (2.73 g.) in 90% formic acid (50 ml.) was subjected to catalytichydrogenation in the presence of 10% palladium carbon (0.25 g.) underatmospheric pressure. After the absorption of hydrogen gas stopped, thecatalyst was filtered off. The filtrate was heated with reflux for anhour and the formic acid was distilled oflf under reduced pressure.Water was added to the residue and the solvent was distilled off. Inorder to remove'the formic acid, there were repeated twice theprocedures of dissolution of the residue and distillation of thesolvent. To the residue was added N sodium hydroxide (50 m1.) and thesolution was heated for 20 minutes on a boiling water bath. Aftercooling, N hydrochloric acid (50 ml.) was added to the reaction mixture.Precipitated crystals were collected by filtration and Washed with waterto give 4-(6-aminopuriu-9-yl)-4-deoxy-D-erythronic acid (2.02 g.). M.P.279 C. (decomp).

In the similar manner, there are obtained the following compounds:

4- 6-arniuopurin-9-yl -4-deoxy-D-erythronamide [M.P. 264 to 268 C.(decomp.)]; 4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronic acid [M.P. 215C. (decomp.)]; 4-( 2-amino-6-hydroxypurin-9-yl -4-deoxy-D-erythronicacid [M.P. 223 C. (decomp.)];4-(6-hydroxypurin-9-yl)-4-deoxy-D-erythronamide [M.P. 247 C. (decomp.)];4-(6-ethyl-amiuopurin-9-yl)-4-deoxy-D-erythronic acid [M.P. 242 to 243C. (decomp.)]; 4-(6-diethylaminopurin-9-yl)-4-deoxy-D-erythronic acidhydrochloride [M.P. 187 C. (decomp.)];4-(6-aminopurin-9-yl)-4-deoxy-L-threonic acid [M.P. 291 to 293 C.(decomp.)]; 4-(purin-9-yl)-4-deoxy-D-erythronic acid [M.P. 230 C.(decomp.)]; N-ethy1-4-(6-amiuopurin-9-yl)-4-deoxy-D-erythronamide [M.P.166 to 168 C. (decomp.)]; N,N-diethyl-4- (6-aminopurin-9-yl-4-deoxy-D-erythronamide [M.P. 192 to 193 C. (decomp.)]; 4-2-methyl-G-aminopurin-B-yl) -4-deoxy-D-erythronic acid;4-(6,8-diaminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(2-aminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(8-aminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(2,6-dihydroxypurin-9-yl) -4-deoxy-D-erythr0nic acid [M.P. 204 to 206C. (decomp.)]; 4-(6-butyrylaminopurin-9-yl)-4-deoxy-D-erythronic acid;4-(2,6-diaminopurin-9-yl)-4-deoxy-D-erythronic acid, etc.

Example 10 (A) A solution of 4-(S-amino-4-cyano-1-imidazolyl)-4-deoxy-D-erythronic acid (500 mg.) in diethoxymethyl acetate (5 ml.)was heated under reflux for 3 hours. After cooling, the solvent wasdistilled off under reduced pressure. The residue was dissolved intomethanolic ammonia.

The solution was allowed to stand for 24 hours. The methanol wasdistilled off under reduced pressure, and the residue was dissolved intowater. The aqueous solution was adjusted to pH 3 with 5% hydrochloricacid. Precipitated crystals were collected by filtration and washed withwater and then methanol to give 4-(6-aminopuriu-9-yl)-4-deoxy-D-erythronic acid mg). M.P. 279 C. (decomp.). Ammonium salt: M.P. 265 to267 C. (decomp.). Sodium lLP. 272 C. (decomp) Hydrochloride: M.P. 198 toIn the similar manner, there are obtained the followmg compounds:

29 N-ethyl-4-(6-aminopurin-9-yl)-4-dexoy-D-erythronamide [M.P. 166 to168 C. (decomp.)]; N,N-diethyl-4- (6-aminopurin-9-yl-4-dexoy-D-erythronamide [M.P. 192 to 193 C. (decomp.)];4-(6-amino-8-hydroxypurin-9-yl) -4-deoxy-D-erythronic acid [M.P. 215 to217 C. (decomp.)]; 4-(2-methyl-6-aminopurin-9-yl)-4-deoxy-D-erythronicacid; 4-(2,6-diaminopurin-9-yl)-4-deoxy-D-erythronic acid,

etc.

Example 11 (A) To a solution of adenine (1.35 g.) in dimethylsulfoxide(25 ml.), sodium hydride (0.48 g.) was added. The mixture was stirred atroom temperature for an hour and then at 50 C. for 30 minutes. To themixture was added 2,3-O-isopropylidene-D-erythronolactone (1.58 g.), andthe reaction mixture was stirred at 120 C. for 20 hours. Thedimethylsulfoxide was distilled oif under reduced pressure from thereaction mixture, and the residue was dissolved in water. The aqueoussolution was washed with ether, and the water layer was adjusted to pH 3with hydrochloric acid and then allowed to stand. Precipitated crystalswere collected by filtration and Washed with water to give4-(6-aminopurin-9-yl)-4-deoxy- 2,3-O-isopropylidene -D -erythronic acid.On the other hand, the filtrate was condensed under reduced pressure andthe residue was treated with water to give the same substance asobtained above. Yield, 56%. M.P. 214 C. (decomp.) (recrystallized from50% ethanol).

(B) A solution of adenine (2.7 g.) in dimethylformamide (45 ml.) wasadded sodium hydride (0.96 g.). The reaction mixture was stirred at roomtemperature for an hour and then at 50 C. for 30 minutes. To the mixturewas added 2,3-O-isopropylidene-D-erythronolactone (3.15 g.). Theresultant mixture was heated under reflux for 8 hours. Thedimethylformamide was evaporated under reduced pressure, and the residuewas dissolved in water. The aqueous solution was washed with ether andneutralized with hydrochloric acid. The solution was condensed underreduced pressure. The residue was treated with water, and precipitatedcrystals were collected by filtration and dried to give4-(6-aminopurin-9-yl)-4- deoxy-2,3-O-isopropylidene D erythronic acid(3.4 g.). M.P. 214 C. (decomp.). On the other hand, the filtrate wascondensed under reduced pressure, and the residue was treated with waterto give the same substance (0.44 g.) as obtained above. Yield, 65.5%.

(C) A solution of adenine (1.35 g.),2,3-O-isopropylidene-D-erythronolactone 1.58 g.) and potassium carbonate(0.7 g.) in dimethylformamide (20 ml.) was heated for 6 hours underreflux. The reaction mixture was treated as in Example 4(B) to give4-(6-aminopurin-9- yl)-4-deoxy-2,3-O-isopropylidene-D-erythronic acid(0.88 g.). M.P. 214 C. (decomp.). Yield, 30%.

(D) A suspension of adeninl-oxide (1.51 g.)2,3-isopropylidene-D-erythronolactone (2.21 g.) and potassium carbonate(1.38 g.) in dimethylformamide (50 ml.) was heated with stirring for 8hours under reflux. From the reaction mixture, the dimethylformamide wasremoved by distillation under reduced pressure. The residue wasdissolved into a small amount of water, and an insoluble substance wasfiltered off. The filtrate was adjusted to pH 3 with hydrochloric acid.Precipitated crystals were collected by filtration to give6-amino-9-(3-carboxy-2,3- isopropylideneoxypropyl)-purin-l-oxide (0.40g.). M.P. 270 C. (decomp.) (recrystallized from methanol).

(E) A suspension of adenin-l-oxide (1.51 g.),2,3-isopropylidene-D-erythronolactone (2.21 g.) and sodium carbonate(1.06 g.) in dimethylformamide (50 ml.) was heated with-stirring for 12hours under reflux. The reaction mixture was treated as in Example 4(D)to give 6 amino 9 (3 carboxy 2,3 isopropylideneoxypropyl)- purin-l-oxide(1.10 g.). M.P. 270 C. (decomp.) (recrystallized from methanol).

(F) A suspension of adenin-l-oxide 1.51 g.),2,3-isopropylidene-D-erythronolactone (2.21 g.) and sodium carbonate(1.06 g.) in dimethylsulfoxide (50 ml.) was heated with stirring at 160C. for 6 hours. The reaction mixture was treated as in Example 4(D) togive 6-amin0-9-(3- carboxy 2,3 isopropylideneoxypropyl)-purin 1 oxide(1.30 g.). M.P. 270 C. (decomp.) (recrystallized from methanol.

(G) A suspension of adenin-l-oxide (1.51 g.), 2,3-O-isopropylidene-D-erythronolactone (2.21 g.) and sodium carbonate (1.06g.) in dimethylacetamide (50 ml.) was heated with stirring at 160 C. for12 hours. The reaction mixture was treated as in Example 4(D) to give 6-amino 9 (3 carboxy 2,3 isopropylideneoxypropyl)- purin-l-oxide (0.80g.). M.P. 270 C. (decomp.) (recrystallized from methanol).

(H) A mixture of N-ethyladeninc (1.63 g.),2,3-O-isopropylidene-D-erythronolactone (2.20 g.) and sodium carbonate(1.06 g.) in dimethylformamide (32 ml.) was heated with reflux for 24hours. The dimethylformamide was distilled off, and water was added tothe residue. An insoluble substance was filtered ofi, and the filtratewas neutralized with 10% hydrochloric acid (7.3 ml.) and concentrated togive 4-(6-ethylaminopurin-9-yl)-4-deoxy- 2,3-O-isopropylidene Derythronic acid. This substance was further subjected to the procedurefor converting it into 4-(6-ethylaminopurin-9-yl)-4-deoxy D erythronicacid 10% acetic acid (50 ml.) was added to the substance, heated withreflux for 30 minutes and concentrated-The concentrate was adsorbed onan ion exchange resin[OH type IRA 400 (trade name)], the resin waswashed with 0.05 N acetic acid and eluted with 0.5 N acetic acid. Theeluate was concentrated to give 4-(6-ethylaminopurin-9- yl)-4-deoxy Derythronic acid (0.56 g.). M.P. 242 to 243 C. (decomp.) (recrystallizedfrom aqueous ethanol).

UV spectrum: Q 269 m (e=17,4.00).

(I) A mixture of adenine (1.35 g.), benzylideneerthronolactone (2.89 g.)and sodium carbonate 1.06 g.) in dimethylformamide (50 ml.) was heatedwith reflux under stirring for 19 hours. The dimethylformamide wasdistilled off under reduced pressure. The residue was dissolved in water(20 ml.) and filtered. The filtrate was adjusted to pH 3 with Nhydrochloric acid (20 ml.). Precipitated crystals were collected byfiltration, treated with carbon powder and recrystallized twice frommethanol while hot to give 4-(6-aminopurin-9-yl)-4-deoxy-2,3 O-benzylidene D erythronic acid. MJP. 198 to 199 C.

(decomp.).

H 0 UV spectrum. 261 my.

(I) A mixture of adenine-N-oxide 1.51 g.), benzylideneerythronolactone(2.89 g.) and sodium carbonate (1.06 g.) in dimethylformamide (50 ml.)was heated with reflux under stirring for 19 hours. Thedimethylformamide was distilled off under reduced pressure and theresidue was dissolved in water -(20 ml.). The solution was filtered andthe filtrate was neutralized with N hydrochloric acid (20 ml.).Precipitated crystals were collected by filtration and recrystallizedfrom methanol while hot to give 4 (G-aminopurin 9 yl) 4 deoxy 2,3 O-benzylidene (D erythronic acid. M.P. 198 to 199 C. (decomp.).

UV spectrum: A g 261 m (K) A mixture of adenine (1.53 g.),dimethylformamide (27 ml.) and potassium hydroxide (0.84 g.) was heatedat C. for 30 minutes and further at C. for 10 minutes. To the mixturewas added 2,3-O-isopropylidene-D-erythronolactone (1.90 g.) indi-methylformamide (5 ml.), and the reaction mixture was refluxed for 18hours. The dimethylformamide was distilled 011, water was added to theresidue and insoluble substance was removed.

, a 31 The waterlayer was adjusted to pH 3 with 10% hydrochloric acidand vconcentrated. A small amount of water was added to the residue andprecipitated crystals were collected by filtration to give4-(6-amino-purin-9-yl)-4 deoxy-2,3-Oisopropylidene D erythronic acid(0.73 g.). M.P. 214 C (decomp.)..

(L) A mixture of adenine (1.35 g), dimethylfor-mamide (20 1111.), 2,3 Oisopropylidene-D-erythronolactone (1.58. g.) and cesium fluoride (0.75g.) was heated under reflux for 23 hours. The dimethylformamide wasevaporated under reduced pressure, the residue Was dissolved in waterand insoluble material was removed. The aqueous solution was adjusted topH 3 with 10% hydrochloric acid. The solution was condensed underreduced pressure. The residue was treated with water, and precipitatedcrystals were collected by filtration to give 4-(6-aminopurin-9-yl)-4-deoxy-2,3 isopropylidene-D- erythronic acid (0.4g.). M.P. 214 C. (decomp.).

(M) A mixture of adenine (1.35 g.), 2,3 Oisopropylidene-D-erythronolactone (2.20 g), potassium t-hutoxide (1.68g.) and dimethylformamide (27 ml.) was heated under reflux for 24 hours.The reaction mixture was treated as in Example 4 (L) to give4-(6-aminopurin-9-yl)-4- deoxy-2,3 O isopropylidene D erythronic acid(1.41 g.). M.P. 214 C. (decomp.).

(N) A mixture of 6-benzamidopurin (2.40 g.) 2,3 O-isoprpoylidene-D-erythronolactone (2.21 g.) and sodium carbonate (1.06g.) in dimethylformamide (30 ml.) was stirred at 120 to 125 C. for 20hours. The dimethylformamide was removed by filtration and the residuewas dissolved in a small amount of water. The aqueous solution wasadjusted to pH 3 with dilute hydrochloric acid and precipitated crystalswere filtered off. The filtrate was concentrated under reduced pressureand the concentrate was dissolved in acetic acid (50 ml.) and thesolution was heated refiuxively for two hours. The reaction mixture wastreated with carbon powders and concentrated under reduced pressure. Theconcentrate was dissolved in a small amount of water. The aqueoussolution was proved to contain 4-(6-benzamidopurin-9-yl)-4-deoxy 2,3 Oisopropylidene-D-erythronic acid by thin layer chromatography.Precipitated crystals from the aqueous solution were collected byfiltration and recrystallized from water to give4(6-aminopurin-9-yl)-4-deoxy D erythronic acid (0.50 g.). M.P. 279 C.(decomp.).

(O) A solution of adenine (1.35 g.), 2,3 Oisopropylidene-D-erythronolactone (2.40 g.) and sodium bicarbonate('1.26 g.) in dimethylformamide (27 ml.) was heated under reflux for 18hours. The reaction mixture was treated as in Example 4(L) to give4-(6-aminopurin- 9-yl)-4-deoxy-2,3 O isopropylidene D erythronic acid(0.88 g.). M.P. 214 C. (decomp.).

(P) A mixture of 6-methoxypurine (1.50 g.) 2,3-O-isopropylidene-D-erythronolactone (1.90 g.), sodium carbonate (0.64 g.)and dimethylformamide (30 ml.) was heated at 140 C. for 8 hours. Thedimethylformamide was distilled off, after which the residue wasdissolved in water and 10% hydrochloric acid (4.5 ml.) was added to the.aqueous solution. The reaction mixture was concentrated under reducedpressure to obtain an oil of 4-(6- methoxypurin-9-yl) 4 deoxy 2,3 O-isopropylidene D-erythronic' acid. 10% acetic acid (50 ml.) was addedto thus obtained oil and the mixture was refluxed for 30 (Q)-octanamidopurine (1.3 g.), potassium carbonate (0.55 g.), 2,3 0isopropylidene D erythronolactone (1.18 g.) and dimethylformamide (26'ml.) were heated with reflux for 6 hours. The dimethylformamide wasdistilled off and water was added thereto. Insoluble material wasfiltered otf, and the filtrate was adjusted to .pH 3 with 10%hydrochloric acid. The separated oil was extracted with ethyl acetateand the aqueous layer was concentrated. A small amount of water wasadded to the residue. The aqueous solution was proved to contain-4-(6-octanolyamido-purin 9 yl) 4 deoxy-2,3-O-isopropylidene-D erythronic acidby thin-layer chromatography. Precipitated crystals form the aqueoussolution were collected by filtration to give4-(6-aminopurin-9-yl)4-deoxy- 2,3-O-isopropylidene D erythronic acid(0.36 g.). M.P. 214 C. (decomp.).

In the similar manner, there are obtained the following compounds:4-(-6-amino-8-methylpurin-9 yl)-4-deoxy-2,3O-isopropylidene-D-erythronic acid [M.P. 265 C. (decomp.)], etc.

Example 12 (A) A suspension of methyl 4-(6-aminopurin-9-yl)-4-deoxy2,3-O-diacetyLD-erythronate (100 mg.) in N sodium hydroxidesolution (2 ml.) was stirred at room temperature for 3 hours. Thereaction mixture was adjusted to pH 3-4 with hydrochloric acid.Precipitated crystals were collected by filtration, washed with waterand then dried to give 4-(6-aminopurin-9-yl)-4-deoxy-D-erythronic acid(44 mg.) M.P. 279 C. (decomp.). Ammonium salt: M.P. 265 to 267 C.(decomp.). Sodium salt: M.P. 272 C. (decomp.). Hydrochloride: M.P. 198to 201 C.

(B) A solution of 4-(6-benzamidopurin-9-yl)-4-deoxy- D-erythronic acidmg.) in methanol (5 ml.) con taining metallic sodium (50 mg.) was heatedunder reflux for an hour. From the reaction mixture, methanol wasremoved by evaporation under reduced pressure, and the residue wasdissolved in water. The aqueous solution was adjusted to pH 3-4 with 5%hydrochloric acid. The water layer was washed with ether and allowed tostand. The precipitated crystals were collected by filtration, washedwith water and then dried to give 4-(6-a-minopurin-9-yD4-deoxy-D-erythronic acid (36 mg.). M.P. 279 C. (dc-5 comp).

(C) 4-(6 aminopurin-9-yl)-4-deoxy-D-erythronamide mg.) was dissolvedunder heating in 10% sodium hydroxide solution (5 ml.). The solution wasrefluxed under heating for 1.5 hours, adjusted to pH 3 with dilutehydrochloric acid and allowed to stand. Precipitated crystals werecollected by filtration and washed with water to give4-(6-aminopurin-9-yl)-4-deoxy-D-erythr0nic acid (8 mg). M.P. 279 C.(decomp.).

(D) A solution of 4-(6-arninopurin-9-yl)-4-deoxy-2,3-

O-isopropylidene-D-erythronic acid (150 mg.) in 10% formic acid (3 ml.)was heated on a water bath for 30 minutes. The reaction mixture wascondensed under reduced presure, and water was added thereto. Theprecipitated crystals were collected by filtration, washed with waterand then dried to give 4-(6-aminopurin-9-yl)-4- deoxy-D-erythronic acidmg). M.P. 279 C. (decomp.).

(E) 4-(6 amino-8-methylpurin-9-yl) 4 deoxy-2,3-O-isopropylidene-D-erythronic acid (400 mg.) was dissolved in 20% aceticacid (10 ml.) under heating. The solution was heated for 30 minutesunder reflux; treated with carbon powder and then filtered. The filtratewas allowed to cool, and precipitated crystals were collected byfiltration and washed with water to give crystals (232 mg.) of 4 (6amino 8 methy1purin-9-yl)-4-deoxy-D-- erythronic acid. M.P. 281 C.(decomp.)(recrystallized from water).

UV spectrum: 7.5;; 263 my $14,300

(F) G-amino 9 (3 carboxy-Z,3-O-isopropylidene-;

dihydroxypropyl)-purin-1-oxide (300 mg.) was suspended in 10% aceticacid (10 ml.). Thesuspension was heated under reflux for 30 minutes. Asmall amount of carbon

